Testing in Service-Oriented Environments...i | CMU/SEI-2010-TR-011 Table of Contents Abstract vii 1 Introduction 1 1.1 Organization of This Report 2 2 Testing in a Service Oriented

Testing in Service-Oriented Environments

Ed Morris

William Anderson

Sriram Bala

David Carney

John Morley

Patrick Place

Soumya Simanta

March 2010

TECHNICAL REPORT

CMU/SEI-2010-TR-011 ESC-TR-2010-011

Research, Technology, and System Solutions (RTSS) Program Unlimited distribution subject to the copyright.

http://www.sei.cmu.edu

http://www.sei.cmu.edu

This report was prepared for the

SEI Administrative Agent

ESC/XPK

5 Eglin Street

Hanscom AFB, MA 01731-2100

The ideas and findings in this report should not be construed as an official DoD position. It is published in the

interest of scientific and technical information exchange.

This work is sponsored by the U.S. Department of Defense. The Software Engineering Institute is a federally

funded research and development center sponsored by the U.S. Department of Defense.

Copyright 2010 Carnegie Mellon University.

NO WARRANTY

THIS CARNEGIE MELLON UNIVERSITY AND SOFTWARE ENGINEERING INSTITUTE MATERIAL IS

FURNISHED ON AN "AS-IS" BASIS. CARNEGIE MELLON UNIVERSITY MAKES NO WARRANTIES OF

ANY KIND, EITHER EXPRESSED OR IMPLIED, AS TO ANY MATTER INCLUDING, BUT NOT LIMITED

TO, WARRANTY OF FITNESS FOR PURPOSE OR MERCHANTABILITY, EXCLUSIVITY, OR RESULTS

OBTAINED FROM USE OF THE MATERIAL. CARNEGIE MELLON UNIVERSITY DOES NOT MAKE

ANY WARRANTY OF ANY KIND WITH RESPECT TO FREEDOM FROM PATENT, TRADEMARK, OR

COPYRIGHT INFRINGEMENT.

Use of any trademarks in this report is not intended in any way to infringe on the rights of the trademark holder.

Internal use. Permission to reproduce this document and to prepare derivative works from this document for

internal use is granted, provided the copyright and "No Warranty" statements are included with all reproductions

and derivative works.

External use. This document may be reproduced in its entirety, without modification, and freely distributed in

written or electronic form without requesting formal permission. Permission is required for any other external

and/or commercial use. Requests for permission should be directed to the Software Engineering Institute at

[email protected].

This work was created in the performance of Federal Government Contract Number FA8721-05-C-0003 with

Carnegie Mellon University for the operation of the Software Engineering Institute, a federally funded research

and development center. The Government of the United States has a royalty-free government-purpose license to

use, duplicate, or disclose the work, in whole or in part and in any manner, and to have or permit others to do so,

for government purposes pursuant to the copyright license under the clause at 252.227-7013.

mailto:[email protected]

i | CMU/SEI-2010-TR-011

Table of Contents

Abstract vii

1 Introduction 1 1.1 Organization of This Report 2

2 Testing in a Service Oriented System 3 2.1 Artifacts to be Tested 4 2.2 Perspectives, Roles, and Responsibilities 6

3 Testing Challenges 9 3.1 SOA Infrastructure Testing Challenges 9 3.2 Service Challenges 10 3.3 Environment for Testing 12

4 Testing Functionality 13 4.1 Testing SOA Infrastructure Capabilities 13 4.2 Testing Web Service Functionality 14 4.3 Fault Injection 15 4.4 Regression Testing 15 4.5 Testing Business Processes That Span Traditional Boundaries 17

4.5.1 Process for End-to-End Testing 18 4.5.2 Defining End-to-End Threads and Establishing Test Scenarios 19 4.5.3 Identifying Dynamic Mission Threads 20 4.5.4 Identifying and Initializing the Context and Test Payloads 21 4.5.5 Capturing and Analyzing Results 21

5 Testing For Interoperability 23 5.1 Defining Interoperability Levels 23 5.2 Interoperability in Infrastructure 25

5.2.1 Testing Within the Infrastructure 25 5.2.2 Testing Between Infrastructures 25

5.3 Interoperability in Services 26 5.4 End-to-End Interoperability 26

6 Testing for Security 29 6.1 Thread Modeling and Attack Surface 29

6.1.1 Threat Modeling 29 6.1.2 Attack Surface 30 6.1.3 Combining Threat Modeling with Attack Surface 30 6.1.4 Use of Threat Modeling with Attack Surface in SOA Testing 31

6.2 Testing SOA Infrastructure Security 31 6.3 Testing Web Service Security 32 6.4 Web Service Verification 33

7 Testing for Other Quality Attributes 35 7.1 Performance 35 7.2 Reliability 37

8 Testing for Standards Conformance 39

9 Test-Related Strategies 41

ii | CMU/SEI-2010-TR-011

9.1 Test-Driven Development 41 9.2 Design-by-Contract 42 9.3 Governance Enforcement 42 9.4 Runtime Monitoring 43 9.5 Service Level Agreements 44 9.6 Assurance Cases 45

10 Summary 47

Appendix A List of Acronyms Used 49

Appendix B Consolidated List of Recommendations 51

Appendix C Key Attributes for Testing Web Services 55

Appendix D Testing Process Preconditions and Deliverables 59

References 63

iii | CMU/SEI-2010-TR-011

List of Figures

Figure 1: Mission Thread Testing Process 19

Figure 2: SOA Interoperation Stack Showing Levels of Interoperability 23

Figure 3: Threats and Attack Surfaces 31

Figure 4: Overview of the Web Service Verification Process 34

Figure 5: Potential Performance Bottleneck Points in a Web Service Invocation 36

Figure 6: Enterprise Service Management (ESM) in an SOA Environment 44

iv | CMU/SEI-2010-TR-011

v | CMU/SEI-2010-TR-011

List of Tables

Table 1: Implications of Service-Orientation on Quality Attributes 3

Table 2: Important Roles in an SOA Environment 6

Table 3: Recommendations for Testing Selected Infrastructural Capabilities 13

Table 4: Types of Threats and Typical Countermeasures 30

Table 5: Performance Metrics 36

vi | CMU/SEI-2010-TR-011

vii | CMU/SEI-2010-TR-011

Abstract

This report makes recommendations for testing service-oriented architecture (SOA) implementa-

tions consisting of infrastructure, services, and end-to-end processes. Testing implementations of

SOA infrastructure, services, and end-to-end processing in support of business processes is com-

plex. SOA infrastructure is often composed of multiple, independently constructed commercial

products―often from different vendors―that must be carefully configured to interact in an ap-

propriate manner. Services are loosely coupled components which are intended to make minimal

assumptions about where, why, and under what environmental conditions they are invoked. Busi-

ness processes link together multiple services and other systems in support of specific tasks.

These services and systems may operate on remote platforms controlled by different organizations

and with different SOA infrastructures. Such complications make it difficult to establish appropri-

ate environments for tests, to ensure specific qualities of service, and to keep testing up-to-date

with changing configurations of platforms, infrastructure, services, and other components.

viii | CMU/SEI-2010-TR-011

1 | CMU/SEI-2010-TR-011

1 Introduction

Service-oriented architecture (SOA) has quickly become a dominant paradigm for distributed,

interoperating, software systems of systems.1 Three interrelated concepts need to be distinguished:

SOA, services, and business processes.

1. SOA is a way of designing, developing, deploying, and managing systems that is characte-

rized by

a. coarse-grained services that represent reusable business functionality

b. service consumers that are clients for the functionality provided by the services, such as

end-user applications, internal and external systems, portals, or even other services (i.e.,

composite services) and that compose applications or systems using the functionality

provided by these services through standard interfaces

c. an SOA infrastructure that provides means to connect service consumers to services [1].

2. Services are reusable components that represent business tasks, such as customer lookup,

weather, account lookup, or credit card validation. Services represent a task or step in a busi-

ness process and they can be globally distributed across organizations and reconfigured to

support new business processes.

3. Business processes (also referred to as mission threads by some government organizations)

are a defined set of tasks that produce specific capabilities or products. Each task is com-

posed of one or more services that are integrated to form the process.

While there are many potential implementations of the SOA architectural style, web services that

include HTTP, SOAP, WSDL, and UDDI provide one of the most widely adopted approaches to

SOA implementation [2,3,4,5].2 Because web service implementations are so widespread, com-

mercial tool support is available for many aspects of the engineering process, including testing.

SOA implementations are possible using other technologies and standards; however, commercial

tool support is less widely available for these other implementations.

Whichever technologies and standards SOA implementations use, it is challenging to test those

implementations, for various reasons. For instance, services are often outside the control of the

organization consuming the service (i.e., service builders, service owners, and service consumers

may each be from different organizations), leading to potential mismatches and misunderstand-

ings between parties. In addition, SOA implementations are often highly dynamic, with frequently

changing services and service consumers, and varying load on services, SOA infrastructure, and

the underlying network. Consequently, it is normally very difficult to replicate all possible confi-

gurations and loads during the testing process.

The scope of an SOA testing effort includes which aspects should be tested for (or against), the

elements to be tested, and artifacts produced during the testing effort. Typically, testing hand-

1 Maier [61] defines a system of systems as one in which there is managerial independence, operational inde-

pendence, and geographic distribution of the elements; continuing evolution; and emergent behaviors such that

the system of systems exhibits behaviors apart from those of individual elements

2 Acronyms used in this report are identified in Appendix A.

http://en.wikipedia.org/wiki/Tasks

2 | CMU/SEI-2010-TR-011

books include strategies for testing the completeness, correctness, and accuracy of requirements,

architecture, design, documentation, and many other non-executable artifacts. This report does not

address testing of non-executable artifacts. Here, we focus on dynamic testing [6], which includes

unit, integration, and systems-level testing of executable software (for both functional and non-

functional attributes). For information about the broader view of testing, see Kaner, Falk, and

Nguyen, and Whittaker [6,7].

1.1 Organization of This Report

Section 2 introduces foundational material about SOA implementation testing. Three aspects to be

tested are described: functionality, non-functional attributes, and conformance. In addition, the

elements to be tested—SOA infrastructure, web services, and end-to-end threads—are discussed.

Finally, key roles such as service developer, service provider, and service consumer are examined.

Section 3 details the challenges faced when testing SOA implementations; Sections 4–8 provide

specific guidance for testing the aspects of the implementation. Section 9 discusses other tech-

niques that can be used in conjunction with traditional testing in order to enhance the testing

process. Section 10 is a short summary of the report.

Throughout the report, we highlight recommendations for good SOA implementation testing prac-

tice; the recommendations are compiled in Appendix B.

3 | CMU/SEI-2010-TR-011

2 Testing in a Service Oriented System

At the highest level, testing in an SOA implementation does not differ from testing in traditional

systems. Specifically, testing must address

functionality: The functional capabilities must be tested to determine whether requirements

and other expectations will be (or are being) met. For example, functional testing in the SOA

infrastructure can verify that services are made available correctly (i.e., they are published),

that the services can be located, and that connections can be established (called find and

bind).

non-functional attributes: The non-functional characteristics that are essential for determin-

ing fitness for operational use, also called quality attributes, must be tested. Table 1 is a list

of some quality attributes [8] considered important, with implications from service-

orientation on testing.

conformance: Testing can verify conformance to specific guidelines and standards that the

organization has chosen to adopt. For implementations based on web services, there are

many standards and guidelines that can be found from the W3C [9] the WS-I [10], and

OASIS [11].3 In addition, many organizations develop standards and guidelines specific to

their lines of business.

Table 1: Implications of Service-Orientation on Quality Attributes

Quality Attribute Implications of Service Orientation on the Quality Attribute

Availability A service may not be under the direct control of the service consumer. Therefore,

there is no guarantee of availability.

Multiple identical instances of a service may be used to enhance availability, lead-

ing to a need to test consistency between the instances.

Diverse instances of a service may be used, complicating testing as each imple-

mentation must be tested.

Modifiability A service-oriented system is meant to be easy to modify. Further, because its in-

ternal implementation (e.g., program language, structure) is hidden from service

consumers, a service implementation can be changed as long as the service inter-

face is unchanged. The interface can also be modified as long as prior functionality

is maintained (i.e., functionality can be added incrementally). Testing is compli-

cated in cases where the testers do not have access to service implementations. In

such a case, testing becomes similar to a COTS (commercial off-the-shelf) envi-

ronment (i.e., black box with significant trust issues)

A new version of a service may not be backwards compatible with earlier, tested

versions of the service.

Interoperability Services are meant to be interoperable by publishing their service interfaces and

using common protocols, however, there is minimum support for semantic intero-

perability.

SOA infrastructures can differ in the way they implement features (e.g., security).

This makes it difficult to invoke services across differing infrastructures. This prob-

lem is sometimes referred to as infrastructure federation.


4 | CMU/SEI-2010-TR-011

Quality Attribute Implications of Service Orientation on the Quality Attribute

Performance If implemented using web services, service orientation has a negative effect on run-

time performance (i.e., response time and throughput) primarily because

XML serialization, deserialization, validation, and transformation produce per-

formance overhead.

The presence of meta information makes web services messages more verbose

and hence larger in size; therefore, the messages need more bandwidth.

Adaptability Services are intended to be rapidly adaptable to changing business or mission de-

mands. Because the environment is changing rapidly, testing must balance between

the desire for full testing and the need for rapid deployment. Automated test suites

and regression testing techniques become critical.

Reliability While standards are available to help with message-level reliability, service-level

reliability is still implementation specific. Tests need to be developed for the failures

that derive from the distributed nature of an SOA-based system. For example, testing

should analyze the behavior when an invoked service is unavailable.

Security Service consumers can reuse existing services; however, this advantage often comes

at a price. An end-to-end thread can cross trust boundaries. Testing must validate

that security is maintained even when information flows across untrusted networks

[12].

2.1 Artifacts to be Tested

The functional, non-functional, and conformance characteristics to be tested should be considered

in the context of the artifacts of a service-oriented system that are available for testing, specifical-

ly the SOA infrastructure, the services, and the service consumers. Note that service consumers

may be services that invoke other services, or they may be composite services, or even end-to-end

threads performing an enterprise-level capability.

SOA Infrastructure

The SOA infrastructure typically consists of capabilities and services to register and discover ser-

vices, manage metadata, provide security, and deliver messages. The infrastructure may be com-

posed of custom-developed software, commercial products, or some combination of custom,

commercial, and open source capability. An SOA infrastructure stack typically consists of at least

the following

a registry

an enterprise service bus (ESB)

application servers

web servers

data stores and databases

However, there is wide variation in the SOA infrastructure capabilities provided by commercial

vendors, in terms of (1) core elements provided by the infrastructure stack; (2) tools to support

developing, integrating, testing, and other software engineering activities; and (3) capabilities,

such as a repository or support for security (e.g., services for authentication or authorization of

access).

5 | CMU/SEI-2010-TR-011

Web Services

Testing of web services includes testing individual services and composites of services. An indi-

vidual web service (also called an atomic web service) typically provides coarse-grained, busi-

ness-level capability. The elements of a web service from a testing perspective are the service in-

terface, service implementation, message format, message payload, and service level agreement

(SLA).

Composites involve multiple web services that interact to provide a capability. Web service or-

chestration and web service choreography are two types of composites [13,14]commonly found in

SOA environments.

Web service orchestration directs the actions of one or more individual web services such

that they work together to perform some useful function. Important elements of a web ser-

vice orchestration are the composition code (e.g., WS-BPEL code), the individual web ser-

vices, and the infrastructure elements and capabilities used to realize the orchestration.

Orchestration (quoting from a BPTrends online column) [15]:

Defines a single master controls of all aspects of a process (top-down approach)

Supports a graphical view of the sequence

Easily maps to SOA

Is usually simpler to start with; but often harder to scale to more complex processes

Is driven by the graphical sequence model, i.e. function follows form

Represents the state-of-the-practice, and is supported by the majority of tools

Web service choreography involves cooperating web service participants, in which services

act as peers involved in interactions that may be long-lived and rely on state information to

direct behavior (i.e., stateful interactions). The goal of these interactions is common and

complementary behavior of the participants that cumulatively accomplishes a business goal.

Choreography (quoting from an BPTrends online column) [15]:

The overall process behavior “emerges” from the working of its parts (bottom up). No

global perspective is required

Complex work processes are decomposed into work agendas where each autonomous

element controls its own agenda

Easily maps to event and agent based systems

Is usually more difficult to start, but often easier to scale to complex processes

Graphical representations can be derived from the process, i.e. form follows function

Represents the state-of-the-art, and is gaining support with emerging tools

End-to-End Threads

End-to-end threads are the combination of humans, applications, services, back-end applications,

and databases that utilize the SOA and network infrastructure to perform a business task.4 End-to-

end threads include services along with other interacting components (human, functional, infra-

structural), along with the operating environment.

4

Along with end-to-end threads, SOA-based applications are tested in this aspect. For simplicity, we use end-to-end thread (or threads) to stand for both types of composites.

http://en.wikipedia.org/wiki/Web_Service

6 | CMU/SEI-2010-TR-011

Recommendation for SOA Testing

Rec. 1: Develop an SOA test strategy that accounts for SOA infrastructure elements, web services

(individual and composites), and end-to-end threads.

2.2 Perspectives, Roles, and Responsibilities

As indicated in Table 2,5 there are several roles that organizations and individuals play in devel-

oping an SOA implementation. Each role is important in SOA testing, and failure to define the

role-specific expectations regarding testing can lead to problems in testing and issue resolution.

For example, it is important to determine the role of a COTS vendor in testing and resolving is-

sues with its product in the user’s context. Clear expectations can help avoid the finger-pointing

that sometimes occurs when products do not interact as expected or promised. Likewise, defining

the role of individual service providers in relation to testing of composites (orchestrations and

choreographies) or end-to-end threads simplifies the processes of setting up the environment, ex-

ecuting tests, and analyzing results.

Table 2: Important Roles in an SOA Environment

Role Action Recommendation for SOA Testing

Service developer Creates the interface of an individual

service and its underlying implementa-

tion by using an existing component and

wrapping it as a service or forming the

service implementation ―from scratch‖

Rec. 2: Establish guidelines for testing the

service before it is ready for use either

by the service consumers or the ser-

vice integrator.

Service provider Provides services. A service provider

may or may not be the developer of the

service; however, a service developer

can also be a service provider.

Rec. 3: Establish clear lines of testing and

customer support responsibility that al-

low for distinctions between the roles

of service developers and service pro-

viders.

Service consumer Uses a service (individual or composite)

directly

Rec. 4: Develop governance processes that

support service consumers in the iden-

tification of use cases and the tests

necessary to achieve appropriate as-

surance about performance of the ser-

vice within those use cases.

Service integrator Uses existing services (individual or

composite) either to create composite

services or to create an end user appli-

cation

Rec. 5: Develop guidelines for testing compo-

sites of various types, including com-

posites that implement capabilities

supporting pre-defined mission threads

and ad hoc composites that reflect at-

tempts to address emerging needs.

Rec. 6: Develop guidelines for testing compo-

sites employing the range of composi-

tion mechanisms expected (e.g., WS-

BPEL defined, application-embedded

composites, WS-CDL).

5 The table is an extension of roles identified in ―Testing services and service-centric systems: challenges and

opportunities‖ [66].

7 | CMU/SEI-2010-TR-011

Role Action Recommendation for SOA Testing

Infrastructure

provider

Provides the necessary SOA infrastruc-

ture middleware (e.g., ESB) and infra-

structural mechanisms such as service

discovery to service providers, service

consumers, and service integrators

Rec. 7: Develop guidelines and governance

processes for testing/verification of

new and revised infrastructure capa-

bilities, including notification of users

of infrastructure changes and trig-

gers for retesting.

Rec. 8: Develop policies for the type and

level of testing support provided by

the infrastructure provider to the ser-

vice provider or integrator.

Third-party service

tester or certifier

Validates and potentially certifies wheth-

er a service (individual or composite)

works as expected

Rec. 9: Identify the focus, expectations, and

limitations of third-party test-

ing/certification activities.

End user Uses applications that employ services Rec. 10: Develop policy clearly delineating

the forms of testing performed ac-

cording to SOA roles.

8 | CMU/SEI-2010-TR-011

9 | CMU/SEI-2010-TR-011

3 Testing Challenges

Testing a service-oriented system is made challenging by a number of factors, not least of which

is that most such systems are not only componentized, but also distributed. In addition to the tra-

ditional problems of distributed systems such as communication failure, the nature of service

orientation, where different components may be provided by different organizations leads to addi-

tional challenges. We have already identified the various structural components involved and now

discuss the challenges that each presents.

3.1 SOA Infrastructure Testing Challenges

We have identified five factors that complicate testing of SOA infrastructure: limited technical

information about components, complex configuration of an infrastructure, rapid release cycles

for components in an infrastructure, lack of a uniform view, and variation across an infrastructure.

The infrastructure provider rarely has access to the design information and source code that

is desired for systems with strict quality requirements (e.g., high performance, security, safe-

ty, etc.). While systems with such requirements may choose components from a collection of

previously accredited systems, even systems with less-stringent quality requirements will

face the challenge of testing ―black box‖ components.

An SOA infrastructure consists of a number of software components such as registry, reposi-

tory, ESB, and databases. Typically, most of these are COTS components, rather than cus-

tom components developed to satisfy specific functional or quality requirements. Whenever

the SOA infrastructure is composed of components from different vendors—and even when

it is provided by a single vendor—individual components have unique installation, adminis-

tration, and configuration requirements. Each component must be configured correctly for

testing, and testing results can vary across multiple configurations of the same infrastructure

components.

There may also be multiple patches and service packs available for individual components

which must be aligned. For example, a quick search performed for this report identified sev-

en different software releases (versions, service packs, vulnerability patches) for one com-

mon ESB during the 13-month period from January 1, 2008 through January 31, 2009. This

rapid cycle of updates necessitates an infrastructure testing process that is fast and efficient.

Many individual components in the SOA infrastructure have their own applications for man-

aging, data recording, and optimizing the component. A single unified view that supports the

tester is often not available.

Implementations of web services stacks (the infrastructure that supports various web services

standards) can be inconsistent regarding the COTS, government off-the-shelf (GOTS), open

source, and other products employed; the subsets and versions of SOA standards imple-

mented; and other characteristics. Because COTS products are black boxes, such inconsis-

tencies can complicate testing by introducing factors, such as different error handling me-

thods and inconsistent use of standards that are not understood clearly by developers and

testers.

10 | CMU/SEI-2010-TR-011

3.2 Service Challenges

The following are key testing challenges from an individual (atomic) web service perspective.

unknown contexts and environments: One of the biggest advantages of web services is their

reusability in variety of contexts. From a service developer’s perspective (that is, having re-

sponsibility for unit testing the service), it is not easy to anticipate all situations where a ser-

vice may be used. This lack of knowledge about usage contexts hampers testing, although

being aware of all contexts is not necessarily a solution either. To address this problem, it is

necessary to determine a set of contexts (based on best estimates) and prepare tests in these

contexts.

unanticipated demand and impact on quality of service: Unlike traditional software compo-

nents, a single instance of a web service can be used by multiple consumers. Since the spe-

cific usage of the service (e.g., load, network and infrastructure delay, data) is unknown at

the time of development and deployment, it is difficult to test and verify whether a service

can successfully meet the quality of service (QoS) expectations of users. Doing so requires

testing for performance under different conditions, such as varying loads.

lack of source and binary code: In many cases, the source code and binary code [16] of the

service and its underlying components are unavailable to the service integrator and tester. In

the absence of source and object code, white box testing techniques such as static analysis

are impossible.6 This circumstance is particularly problematic for organizations that maintain

high information assurance standards, since it becomes difficult to verify that a service is not

acting in a dangerous manner. In most cases, these loosely coupled services are black boxes.

Design and code-level information is often not be available to service providers, meaning

that subtle assumptions embedded in the code can only be identified through rigorous test-

ing.

standards conformance: Web services are based on standards that facilitate syntactic intero-

perability. These standards are defined at a high level of abstraction and are required to con-

form to other complementary standards [17]. This level of abstraction leads to significant

variation in actual vendor implementations, creating additional work for the service tester to

verify compliance with standards such as SOAP, REST [18] , XML, UDDI, WSDL, and

HTTP.7 Tools support testing of many of these well-established standards and they should be

used as appropriate. However, tool support is lacking for several recommendations and stan-

dards that are newer and less widely adopted (e.g., WS-Notification [19], WS-Trust [20]).

In addition to the challenges posed by testing individual services, the following challenges ac-

company testing composite services and end-to-end threads:

service availability: Composites use services that may be controlled by multiple service pro-

viders, and testing of a composition requires that the correct versions of all invoked services

are available. Therefore, the schedule for testing the composite is strongly dependent on

schedules for other services outside the control of the testing organization.

6 White box or glass box testing usually is performed with the knowledge of the internals of an SOA element.


11 | CMU/SEI-2010-TR-011

multiple provider coordination: Even when a service integrator has access to all participating

services and components, the individual services may be black boxes to the integrator. Thus,

the service integrator may need to communicate with the teams providing these services in

order to learn about the implementation characteristics of the service. For example, if a par-

ticipating service saves information in a database that is not visible to the integrator, the in-

tegrator will need to work with the service provider in order to get access to that information.

While access to such information may not always be necessary, it will be a common enough

occurrence that the testing will likely encounter need like this in any significant system.

common semantic data model: There will be a large potential for misunderstandings of the

data exchanged unless all services participating in a composite agree on a common semantic

data model. However, achieving consensus on common semantics is a notoriously difficult

job, and it’s critical for the tester to determine that the applications create data consistent

with the data model and that they transform it according to specified rules. Inconsistencies in

how data is understood can be very subtle and show up only in a few situations; as a result,

they may be difficult to identify. For example, consider that two services may use tempera-

ture but one measures in Celsius and the other in Fahrenheit.

lack of a common fault model: Given that services will likely be developed by different ser-

vice developers, for different purposes, it is unlikely that they will subscribe to a common

fault model. Reconciling fault models is as hard as achieving a common data model and

leads to difficulties when testing that service faults are handled appropriately.

transaction management: Different service providers and SOA infrastructures may imple-

ment slightly different transaction management approaches (e.g., they may have different

models of when a change to a data item actually occurs). These differences may only show

up in unusual or race conditions where the split-second timing of multiple transactions leads

to inconsistent states or service failure. Therefore, the correctness and consistency of all

transactions must be tested.

side effects: Because a single service can be part of multiple composites, execution of test

cases for one composite may produce unwanted side effects in others [21] employing the

service. Also, changes in data or state caused by testing can interfere with other service com-

posites or produce unwanted changes in them. Of course, not all services will suffer from in-

terference between threads; indeed, it is desirable to develop services without such interfe-

rence. However, the difficulty for the tester is determining that any given service is free of

side effects.

independent evolution of participating services: The service integrator often has no control

over individual services or their evolution, yet any change in a participating service can re-

sult in a failure of the composite. If it is unaware of service changes, the service integrator

may be unable to identify the source of a failure. Even when it is aware of the changes, the

service integrator still needs to perform a set of regression tests to ensure the proper func-

tioning of the composite.

lack of tool support: Current testing tools and technologies that claim support for composites

often provide the ability to validate whether a business process representation (e.g., WS-

BPEL) is well-formed and check for the existence of the endpoints of the individual web

12 | CMU/SEI-2010-TR-011

services that make up the composite web service. Tool support for more comprehensive test-

ing of composites is an active research area.

3.3 Environment for Testing

A final challenge, but one that is necessary to overcome, is the creation of a testing environment

that is as similar as possible to the deployment environment (a high fidelity copy) that allows

developers to test and integrate services and service orchestrations prior to actual deploy-

ment

testers to design, implement, execute, and manage the testing process,8 and to capture infor-

mation about the functional and quality aspects of SOA services, infrastructures, and end-to-

end threads

Establishing a testing environment is difficult because many deployment environments are widely

distributed, with heterogeneous hardware and software (SOA infrastructure, services, operating

systems, and databases). Because of cost and security, it may not be possible for all organizations

hosting a capability in the deployed environment to mirror those capabilities in a testing environ-

ment.

An alternative involves developing a testing environment that mirrors several key aspects of the

deployment environment and provides workarounds for missing aspects. In some cases, test cop-

ies of deployment infrastructure may be available; in other cases, virtual machines can be stood

up to mirror parts of the infrastructure. This testing environment should be available to developers

for early testing of services and service orchestrations, as well as to testing organizations perform-

ing certification activities. The testing environment should be populated with

a suite of testing tools to manage tests, validate conformance to standards, and analyze run-

time functionality and performance

test data and associated databases sufficient to support the execution of tests

a mechanism to determine the testing/certification status of a service or service orchestration

(end-to-end thread)

versions of deployed infrastructure and services sufficient to support the execution and test-

ing of services/service orchestrations under development and test

a mechanism for stubbing out or simulating services that are not yet developed


Rec. 11: Provide developers with a fully outfitted test environment for early testing of services and

service orchestrations; provide this environment to testing organizations, too, for performing

certification activities.

8 While this report is not about defining a process for testing SOA implementations, we have included some

thoughts about testing process inputs and outputs in Appendix D.

13 | CMU/SEI-2010-TR-011

4 Testing Functionality

4.1 Testing SOA Infrastructure Capabilities

An SOA infrastructure provides capabilities, often in the form of common services that can be

used by a number of business processes. Services are usually composed of COTS components that

are tested by their vendors, which may mask key information (such as the test cases or their con-

text) from the infrastructure provider. Recommendations for testing SOA infrastructure capabili-

ties are shown in Table 3.

Table 3: Recommendations for Testing Selected Infrastructural Capabilities

Infrastructural

Capability

Implication for SOA Testing Recommendation for SOA Testing

Service Registration

Mechanism

The goal of testing service registration is to

ensure that only validated services become part

of the SOA registry. A final testing results report

is sent to the service provider once the auto-

mated testing is complete. It is also possible for

the service providers to submit test cases con-

forming to a standard when they submit a ser-

vice for registration.

Testing the service registration mechanism

involves testing the tools and options provided

by the infrastructure to register a new service. It

also needs to take into account the version

control of services already registered.

Rec. 12: Develop strategies for testing of the

service registration mechanism.

Service and Resource

Discovery Mechanism

Testing the service and resource discovery

mechanism ensures that registered services

and infrastructure resources can be found by

authorized service consumers. Testing also

needs to be performed if the service consumers

can search for the services they require using

various criteria and matching rules.9

Rec. 13: Develop tests to determine whether

authorized service consumers can

find services based on syntactic or

semantic approaches.

Subscription and Noti-

fication Mechanisms

If the infrastructure provides subscription me-

chanisms, then these need to be tested. All

service consumers must be informed when a

new version of a service is registered with the

infrastructure. Service providers and consumers

also require notifications of service level viola-

tions.

Rec. 14: Develop tests that reveal whether

all appropriate service providers

and consumers are notified when a

new version of a service is regis-

tered with the infrastructure or

when service levels are violated.

9 A discovery mechanism can be syntactic or semantic. Syntactic discovery, while easy to implement and test,

has limitations because service consumers may not always be aware of the keywords to use in a search, and the use of just keywords to describe services often ignores their operational characteristics. A semantic ap-proach promises a greater probability that services sought will be found, but requires more testing effort on the part of the infrastructure provider which must test various matching rules for service discovery.

14 | CMU/SEI-2010-TR-011

Infrastructural

Capability

Implication for SOA Testing Recommendation for SOA Testing

Service Usage

Monitoring

Service usage data is a source of information

for service providers in identifying who will be

affected by changes to a service. Monitoring

provides data important for audits and planning

(e.g., security audits, planning for increases in

load).

Rec. 15: Develop a testing strategy for ser-

vice monitoring capabilities.

Service Virtualization Service virtualization creates and manages

virtual endpoints for web services, allowing the

service to be dynamically associated with physi-

cal endpoints in scenarios such as load-

balancing.

Rec. 16: Develop a testing strategy for ser-

vice virtualization features.

4.2 Testing Web Service Functionality

Services provide the main functionality or capability in an SOA environment. An initial step in

testing is to determine whether each service meets its functional requirements. While testing the

functionality of SOA services uses standard component testing methods, it poses a greater chal-

lenge because of the lack of control over many aspects of the test situation, including the services,

SOA infrastructure, and other components with which the service being tested must interact. This

section highlights approaches to address the challenges of testing service functionality.10

The use of stubs to ―mock‖ the behavior of unavailable components is a common software testing

strategy. This method has applied to the testing of services that need to interact with other services

where not all of the dependent elements are in place. Wolff, Godage, and Lublinsky [22,23,24]

show how mocking can be used to test services. Both open source (e.g., Apache Synapse11

) and

commercial implementations (e.g., SOAPSimulator, soapUI) can help service developers to create

mock services for unit testing quickly because not all functionality needs to be tested.

However, this approach has certain limitations including the following:

The quality of the testing result depends on the fidelity of the mock service to the actual ser-

vice. Services that behave in a complex manner are difficult to mock well, because under-

standing the complex behaviors and implementing these behaviors with testing tools is itself

a complex task. This leads to practical limitations of the types of services that can be

mocked.

The behaviors and interfaces of services to be mocked are often not finalized since develop-

ment is not complete: this is why the services must be mocked. This complication inevitably

leads to uncertainty in the reliability of testing results.

QoS cannot be adequately tested if services or other environment components are mocked.

10

Appendix C contains lists of attributes for testing functionality and other aspects of web services.

11 For more on Synapse, go to http://synapse.apache.org/.

http://synapse.apache.org/

15 | CMU/SEI-2010-TR-011

Recommendations for SOA Testing

Rec. 17: Provide support for service mocking, including mocking of services on remote platforms and

infrastructures.

Rec. 18: Integrate service mocking into the development and testing strategies.

4.3 Fault Injection

Fault injection, when used as a standard software testing approach, makes deliberate errors in the

implementation to see if the system can detect the fault and recover from it. When applied to ser-

vice testing, fault injection focuses on determining that services don’t produce unintended beha-

viors or go into unreachable states when unexpected or faulty inputs are provided. This technique

can be applied to both individual web services [25] and composites [26].

Fuzzing is a testing technique supported by many tools that generates invalid data inputs to web

services. The tools capture the results of the ―fuzz‖ and support the analysis of results to deter-

mine whether it compromised the web service.

Examples of types of faults that can be injected are a malformed service interface [27] (e.g., bad

WSDL definition), perturbation in the message [25] (e.g., null values in a SOAP message), and

timing delays in a composite (e.g., a service may timeout if it doesn’t get a response). Fault injec-

tion is also used to test the security, reliability, and performance of a service as discussed in Sec-

tions 6 and 7.


Rec. 19: Develop guidelines for the type of faults that services and service compositions must be

tested for.

A standard testing practice is testing the software to determine whether it handles realistic data

appropriately; such testing applies equally to services. In order to access appropriate test data, the

SLA should document the responsibilities for producing test data sets and appropriate test inter-

faces. As always, care must be taken to obfuscate production data since web services undergoing

testing may not assure the same degree of security as production services, nor are the persons per-

forming the testing guaranteed to be authorized to access production data.


Rec. 20: Formal agreements should be in place with data providers to identify test data sets and test

interfaces.

4.4 Regression Testing

Because of the rapid evolution of an SOA environment, testing cannot be a one-time event. Ser-

vices, service composites, end-to-end threads—and applications using them—continue to evolve.

This section focuses on the specific aspects of regression testing that need to be considered in an

16 | CMU/SEI-2010-TR-011

SOA environment. Regression testing involves testing and identifying bug fixes to ensure that

defects have not been introduced as a result of evolution. Regression testing also attempts to de-

velop some level of assurance that things that were not touched did not break.

Regression testing in SOA environments is challenging because every service composition, busi-

ness process, and other system using a particular web service is affected by changes made to con-

stituent service [21], unlike a component-based context where the new release of a component

affects only the new versions of that component.

A service baseline aids regression testing efforts by making it easier to determine whether new

functionality has introduced defects and to more quickly mitigate the effects of those defects.

Testing tools that provide regression testing capabilities for web services offer the ability to take a

service baseline snapshot, so that subsequent changes can be automatically detected and reported.

Changes in that baseline can serve as triggers that indicate the need to perform regression testing

of end-to end mission threads. Several of these triggers are

upgrades/version changes to requestor/responder application, infrastructure, services in-

voked, back-end systems

upgrades to Service Contracts (WSDL) or SLAs (e.g., changes to expectations for the servic-

es within the mission thread)

changes or revisions to life-cycle management of components

changes in deployment configurations

changes to back-end systems or data sources

changes in a service’s functional behavior or QoS

updates to the rules used by testing tools

deprecation or retirement of a service

An SOA test sandbox is an infrastructure that accurately mirrors the deployment environment. A

test sandbox not only makes regression testing easier, but it also allows the use of automated test-

ing tools that can perform regression testing as soon as new or updated services are deployed after

a successful build process. Service developers can review the results of the automated testing

tools and initiate mitigation where appropriate.

The actual determination of whether to perform regression testing will be based on many factors,

including the nature of changes and the profile of the mission thread. Clearly, an organization will

be more risk-averse with, and therefore more likely to perform regression testing on threads that

can affect human life or cause widespread environmental or economic damage.

17 | CMU/SEI-2010-TR-011


Rec. 21: Establish baselines for services, compositions, and end-to-end threads.

Rec. 22: Establish regression testing triggers for each.

Rec. 23: Establish a regression testing sandbox fitted with appropriate testing and analysis tools to

automate regression testing to the degree possible.

4.5 Testing Business Processes That Span Traditional Boundaries

End-to-end testing in an SOA environment refers to testing of the entire pathway involved in ex-

ecuting a specific mission or business process. For one example, in a military application, Time

Sensitive Targeting (TST) is often considered to have six phases: find, fix, track, target, engage,

and assess. These activities may span a number of application and organization boundaries. They

cover the point from which a potential target is identified to the point when it is no longer consi-

dered a threat. End-to-end testing of this capability in an SOA environment would involve execut-

ing a number of services, applications, and input from humans. The invoked SOA services may be

provided by different U.S. military services and other agencies, and possibly by coalition forces.

End-to-end testing needs to consider:

Decentralized ownership and lack of centralized control: Distributed ownership in an SOA

environment often involves setting up appropriate data and process context in back-end sys-

tems that are outside the control of the end-to-end tester. Also, services may be created by

different service providers, hosted on different infrastructures, and used by a variety of con-

sumers. These complications introduce the need for creating an environment (through nego-

tiation) for testing, testing across common infrastructures, testing across disparate infrastruc-

tures, and coordinating testing with multiple service providers and owners of back-end

systems.

Long-running business activities: SOA implementations often support the business processes

and workflow that constitute long-running business activities. For example, a loan approval

business process could be executed in phases over weeks.

Loosely Coupled Elements: Web services deployed in an SOA environment are loosely

coupled; they make minimal assumptions about the sending and receiving parties, so that

changes in one entity will have minimal impact on the other interfacing entities. The advan-

tage of such loose coupling is that testing becomes an issue of testing the composition

through simple interactions rather than complex ones.

Complexity: An end-to-end implementation is usually an execution pathway though multiple

people, services, composites, and infrastructure capabilities. Information—about specific

services invoked, parameter data passed, and attachments included—is embedded in proto-

cols that are intended to support machine-to-machine interaction.

Regression testing: Changes at any service, node, or component along the pathway exercised

in support of an end-to-end thread may indicate a need for regression testing of the thread.

Maintaining awareness of these changes requires agreements regarding what types of

changes require notification, when such changes are allowed to occur, and how affected par-

ties are notified. An approach to bounding the need for regression testing is that of assurance

18 | CMU/SEI-2010-TR-011

cases (see Section 9.6) which provide a documented chain of reasoning based on evidence to

support a claim. In this case assurance cases could be used to help identify the conditions

under which further regression testing would be required.


Rec. 24: Use approaches such as assurance cases to identify when additional regression testing is

needed.

Rec. 25: Develop a strategy for testing at each of the layers of the SOA interoperation stack.

Rec. 26: Instrument test instances to help identify the sources of failures.

Rec. 27: Perform regression testing to identify the impacts of changes on services, nodes and com-

ponents along the pathway that is exercised.

4.5.1 Process for End-to-End Testing

The basic process for testing end-to-end threads in an SOA environment does not differ from the

high-level steps involved in other testing processes, with one exception: not only must tests be

devised to establish the correctness of predefined mission threads, but additional tests must be

devised to address the potential for dynamically composed mission threads (see Figure 1). Some

details of the steps are unique to SOA environments, as indicated in subsequent sections.

19 | CMU/SEI-2010-TR-011

Figure 1: Mission Thread Testing Process

4.5.2 Defining End-to-End Threads and Establishing Test Scenarios

With SOA as with any other technology that has many possible threads of control—critical

threads must be identified and specifically tested for both functional and quality characteristics.

Several general approaches are used to identify end-to-end threads and establish test scenarios for

SOA environments. Manual approaches analyze mission functions, decompose these functions

into key decision steps and associated conditions, and define and build test cases accordingly. The

following process steps, derived from Sikri [28] are representative of manual processes:

1. Build a tree of high-level functions including inputs, outputs, and execution paths.

2. Identify conditions (e.g., timing, environment, and data) for each function in the tree.

3. Establish test scenarios based on functions and conditions.

4. Build tests cases addressing functions, conditions, and scenarios.

Other techniques are often needed to understand quality of service attributes and relate them to

various scenarios. A technique such as the Carnegie Mellon®

Software Engineering Institute (SEI)

Mission Thread Workshop12

elicits quality attribute needs associated with the end-to-end threads

® Carnegie Mellon is registered in the U.S. Patent and Trademark Office by Carnegie Mellon University.

12 For more information about the Mission Thread Workshop, go to

http://www.sei.cmu.edu/architecture/tools/evaluatingsos/mission.cfm.

http://www.sei.cmu.edu/architecture/tools/evaluatingsos/mission.cfm

20 | CMU/SEI-2010-TR-011

of a systems-of-systems environment [29]. However, for certain types of services (e.g., public

web services on the Internet) where the actual operating context (e.g., expected load and usage,

level of security required, etc.) is unknown until the service is actually being used, it may be ne-

cessary to adopt an incremental approach in which functionality is fielded and the system is then

adjusted to meet QoS goals.

Automated approaches have recently been developed that model mission threads in formal lan-

guages or that capture mission threads and establish test cases from existing modeling language

(e.g., Unified Modeling Language [UML]) artifacts. The resulting structures are suitable for many

types of analysis (e.g., dependency analysis, consistency checking, and test case generation)

[30,31,32]. While these approaches have significant potential for supporting rapid analysis of dy-

namic mission threads, the modeling language techniques are still in the maturing stage, so using

them needs to be done in small settings and with careful attention to results.


Rec. 28: Develop a strategy for identifying the important threads in an end-to-end threads and deco-

rating those threads with both functional and QoS expectations.

Rec. 29: Develop test cases for critical threads that have been identified.

Rec. 30 For certain types of services (e.g., public web services on the internet) where the actual op-

erating context (e.g., expected load and usage, level of security required, etc.) is unknown

until the service is actually being used, it may be necessary to adopt an incremental ap-

proach in which functionality is fielded and the system is then adjusted to meet QoS goals.

4.5.3 Identifying Dynamic Mission Threads

We believe that at this stage of SOA maturity, the use of dynamically composed mission threads

in SOA environments has been oversold. Dynamic composition requires alignment at several lay-

ers of the interoperability stack (see Figure 2 for details) for the services and applications invoked.

Requisite standards supporting such alignment are not yet available. As a result, dynamic compo-

sition in current SOA environments will rely on local conventions and standards that are likely to

be inconsistently defined and hard to enforce across organizations.

Dynamic composition is more likely among services and applications that are recognized as re-

lated and for which local conventions and standards have been established and tested. We recom-

mend that for SOA environments where dynamic composition is anticipated, every effort should

be made to identify and test likely compositions. Such testing is necessary to identify not only

successful operation of the dynamic thread, but also the effects of dynamic threads on network,

SOA infrastructure, individual services, and other critical threads.


Rec. 31: Develop a strategy for identifying and testing likely dynamically composed threads.

Rec. 32: Implement “non-interference” strategies such that other threads cannot compromise function-

ing or QoS in the rest of the end-to-end thread.

21 | CMU/SEI-2010-TR-011

4.5.4 Identifying and Initializing the Context and Test Payloads

Establishing the testing context for end-to-end thread tests is a well-known problem in traditional

testing and continues to be a problem for SOA testing. It involves realistic simulation of the envi-

ronment in terms of capabilities, data, and loading. This section focuses on the specific aspects of

context to consider in end-to-end testing in SOA environments.

SOA environments often depend on a specific data value or other response from a black box ser-

vice. Well-understood principles that need to be continued are to (1) start with agreements with

service providers concerning the type of test data available, as well as rules governing testing of

the services, (2) use tools to simulate the production environment, (3) use data sets with high fi-

delity to enable testing such QoS attributes as performance, and (4) establish realistic loads on

infrastructure components (network and SOA) as well as on the invoked services and related ap-

plications.


Rec. 33: Develop a strategy for cross-site and cross-organizational collaboration to identify test con-

text and data loads.

4.5.5 Capturing and Analyzing Results

End-to-end processing requires that the collaborating services, infrastructures, and applications

not only execute an action as directed but also that the action performs the correct activity. Cap-

turing data regarding the performance of services invoked in an end-to-end test may require in-

strumentation of the services or infrastructures on which they execute. The format of this metric

data differs according to the characteristics of the infrastructure and tools employed. These chal-

lenges can be addressed by making specific decisions on the data that is to be captured, by provid-

ing a logging service and by using a specially instrumented infrastructure.

An automated test tool offers value by collating and consolidating the test results to provide a sin-

gle point of review, making it easier to identify, categorize, and publish defects.13

Testing tools

that are a part of a comprehensive design and development suite offer the added benefit of linking

test plans to requirements, ensuring that the notion of requirements traceability is satisfied.

13

In addition, a recent report from the Aberdeen Group [62] suggests that automated tool support for testing in SOA environments is a critical differentiator between the most sophisticated employers of SOA (―best in class‖) and those that are less sophisticated. Only the related practice of through-life quality management was cited by more best–in-class organizations as being critical to successful SOA.


Rec. 34: Develop a strategy for cross-site and cross-organizational verification of changes in back-end

systems and capturing and analysis of test results.

22 | CMU/SEI-2010-TR-011

23 | CMU/SEI-2010-TR-011

5 Testing For Interoperability

A fundamental assumption of SOA adoption is that the resulting collection of services and infra-

structures will provide the basis for the creation of new end-user applications or end-to-end

threads through reuse of existing services. A consequence of this assumption is the reliance on the

interoperation of services that weren’t specifically designed to interoperate. Interoperation of the

individual components in any distributed environment (in this case, an SOA environment) relies

on agreements at several levels between service requestors and service providers, which makes

the execution of mission threads difficult. A further complication is that interoperation is the inte-

raction between two entities whereas testing traditionally focuses on entities and not their interac-

tions.

5.1 Defining Interoperability Levels

To achieve end-to-end testing, the services have to be interoperable. Figure 2 identifies the types

of agreements that must exist between service consumers and service providers to ensure success-

ful interoperation.

Figure 2: SOA Interoperation Stack Showing Levels of Interoperability

24 | CMU/SEI-2010-TR-011

Agreements need to be made between service providers and service consumers at all levels. The

agreements include the following (reading Figure 2 from the bottom up):

Agreements at the Machine level—Protocols for network-to-network and machine-to-

machine interaction, such that -two heterogeneous systems can exchange data irrespective of

their hardware, system-level software, and network characteristics. For example, an applica-

tion running on an Army tactical network can gain access to and interact with a service sys-

tem running on an Army enterprise-wide network. This level of interoperability calls for

physical, data link, networking, transport, and session layers of the Open Systems Intercon-

nection Basic Reference Model (OSIRM). 14

Agreements at the Syntactic level—Alignment of the structure and syntax of data and control

structures and interactions of applications and services. Within the web services domain, the

major standards include WSDL, SOAP, and, more recently, REST.

Agreements at the Semantic level—Semantic meaning at the application level on data and

control interactions among services. These agreements may reflect shared ontologies across

the interacting components (services, back end systems, etc.) or mechanisms for map-

ping/translating between different semantic models. Technologies used by web services to

establish common semantics for data include general purpose languages like the RDF and

specialized vocabularies like. OWL, OWL-S,15

and WSMO13

have been used to define com-

puter-interpretable definitions of service semantics. The same concept can apply to control

models. For example, for services implementing transactions to successfully interact, there

must be shared semantics for transactions (such as WS-AtomicTransaction or WS-

Coordination) or a mapping across individual transaction models. Unfortunately, technolo-

gies that provide semantic consistency are not as well developed, stable, or accepted as

agreements at the lower levels of the SOA interoperability stack.

Agreements at the Organizational level—Characteristics of predefined mission threads or

business processes, including the associated context and workflows of thread participants, as

well as the appropriate qualities of service required. Some of the necessary agreements at

this level are defined in SLAs. WS-BPEL also provides a language to define an executable

process that involves message exchanges with other systems, such that the message ex-

change sequences are controlled by the WS-BPEL designer [33].

Agreements at the Situational level—Characteristics of specific situation in which mission

threads or business processes are being applied. These characteristics are always unique to a

specific context. For example, consider a soldier calling in air support. While there are exist-

ing processes that are executed when calling in air support, the specifics of the urgency with

which air support is dispatched and how it is delivered will depend on the proximity of the

enemy, air assets available, and many other factors. There are no public standards for this

specific contextual information, but there may be less formal semantics and heuristics that

are applied.

14

Acronyms used in this report are identified in Appendix A.

15 Formerly DAML-S; OWL-S is the Ontology Web Language for Services.

25 | CMU/SEI-2010-TR-011

Only the lowest two layers of the stack (machine and syntactic alignment) are addressed by com-

monly used web service standards. However, the standards that exist allow for testing services in

isolation for their conformance to those standards.

5.2 Interoperability in Infrastructure

The SOA infrastructure provides components for the lower two layers of the interoperability stack

and, as such, is most amenable to testing for conformance to well-defined standards such as those

provided by W3C. Such conformance testing is discussed later (see Section 8); however, there is

other infrastructure testing to be performed. Specifically, it is important to test that the compo-

nents within any one infrastructure interoperate appropriately and, where needed, that there is ap-

propriate interoperability between infrastructures.

5.2.1 Testing Within the Infrastructure

Typically the SOA infrastructure will be composed of one or more COTS products that have been

brought together to form a coherent infrastructure satisfying the organization’s needs. The prod-

ucts should be selected through an evaluation process that enables the developers to select the

products most suited to satisfy the requirements. The test community can participate in the evalua-

tion process using their expertise in testing as the mechanism for evaluating the products. Such

evaluation should consider not only the features of the individual products but also how well the

products fit with the rest of the candidate or already-selected products. Once the infrastructure has

been assembled, testing can be used to develop confidence that the infrastructure meets the needs.

We have already discussed testing the functionality of the infrastructure (See Section 3.1). How-

ever, additional testing could include testing for other quality attributes as well as simple assur-

ance that the infrastructure provides the basic connectivity between service consumers and pro-

viders.

5.2.2 Testing Between Infrastructures

Increasingly, SOA infrastructures are joined with other SOA infrastructures; it becomes essential

to identify these configurations and to test to ensure that they federate as required. Some federa-

tion configuration types are

homogenous infrastructure: This is essentially a horizontal scaling of the SOA infrastructure

where the federated infrastructures are different instances from the same base. Testing this

federation primarily involves checking connectors between the instances. For example, if the

same ESB product is used by all infrastructure nodes, the main testing task is to ensure that

the connection between two instances of an ESB by the same vendor functions as desired.

heterogeneous infrastructure: This configuration contains nodes that are different—

sometimes the difference may only be in terms of versions; it is more common than the ho-

mogeneous type because nodes are often planned, implemented, and upgraded separately.

hybrid infrastructure: In this configuration, some nodes are identical and others are different;

testing will require tactics from both homogeneous and heterogeneous infrastructure testing.

Regardless of the nature of the federation, it is important to perform the testing that would be ap-

plied to a single infrastructure, but across the federation in order to provide confidence that the

federation behaves as a single ―virtual‖ infrastructure. Capabilities of particular importance are

26 | CMU/SEI-2010-TR-011

federated identity management and discovery. Without appropriate interoperation between the

infrastructures in at least these areas, the federation will not achieve the organization’s aims.


Rec. 35: Develop a strategy to identify and test the capabilities of SOA infrastructures that are needed

to federate the infrastructure.

5.3 Interoperability in Services

Services are found at both layers two and three of the interoperability stack (Figure 2), with infra-

structure services tending towards being in layer two and services providing business functionali-

ty tending towards layer three. Regardless of the source of the services (infrastructure or busi-

ness), testing them for interoperability can be handled in the same way, through means of

syntactic, semantic, and end-to-end interoperability testing. It should be noted that interoperability

is a property that exists between two services and is not a property inherent in the services them-

selves; thus testing services for interoperability becomes largely a matter of testing the service

interfaces’ adherence to standards.

When web services are being used, testing for syntactic interoperability can be performed by de-

termining that the services conform to the appropriate standards (see Chapter 8). Even when web

services are not being used, the SOA infrastructure will have a defined collection of protocols that

it supports and syntactic testing is an issue of determining that the service adheres to those proto-

cols.

Layer three describes semantic interoperability between services, which poses a problem for test-

ing the meaning of service interoperation. In order for services to be semantically interoperable,

they must perform according to expectations, thus a basis for interoperability is that each service

meets its specification, such testing has already been discussed in Section 4.2.

A requirement, though, for two services to be able to interoperate semantically is that they agree

on the data to be communicated. To the extent that the data models are well described, either in

common ontologies or in ontologies that can be mapped to each other, the test community can test

the potential for interoperation by ensuring that the service interface adheres to the defined mod-

el(s). Clearly this isn’t sufficient for full interoperability testing; however, even such minimal

checking will be of benefit to the service developers.


Rec. 36: Develop a list of interoperability standards that services must comply with, and consider of-

fering an interoperability compliance check as a service to developers.

Rec. 37: Develop a list of data models that services must use and consider offering a compliance

check as a service to developers.

5.4 End-to-End Interoperability

End-to-end interoperability may be found at the top two levels of the interoperability stack

(Figure 2). At level four, two or more organizations align their business processes with each other

and an end-to-end thread may cross the organizational boundaries, invoking services owned and

27 | CMU/SEI-2010-TR-011

operated by each other. Level five of the stack allows for the development of end-to-end threads

in a dynamic fashion in order to meet a specific demand. No matter how the thread arises, the is-

sues for testing are the same: to ensure that a sequence of discrete steps (the services) can be in-

voked even though they are geographically separate and owned by different organization and that

the invocation leads to desirable behavior.

Given that the number of services is potentially large, the number of possible interactions grows

exponentially, and not all interactions could have meaning, it is clearly not possible to test all inte-

ractions to ensure that the services are semantically interoperable. Testing interactions should be

largely performed in some context, specifically that of known end–to-end threads. Composite ser-

vices, such as those defined in, say, Business Process Execution Language (BPEL), are a special

case of end-to-end threads. The interfaces to composite services can be tested in the same way

that services are tested, and the interactions between the services within the composite can be

tested in the same way that end-to-end threads are tested.

As a result, it is difficult to ensure consistency at the semantic and organization levels.16

The

most common strategy for achieving consistency at these levels is to develop predefined mission

threads (i.e., static threads) and test to ensure that consistency is achieved in use of vocabulary

and organizational interactions. Consistency at the situational level will often involve human-to-

human communication of the nuances of specific contexts and therefore it is difficult (or more

likely impossible) to make entirely consistent.

To address these challenges, a set of guidelines can be followed that includes

thoroughly test the services using the techniques defined in Section 4.2

test adherence to data standards

functionally test the defined threads

test the threads for performance, security, and other quality attributes

Failure at any of level in the stack can lead to a failure of mission thread. However, up to this

point (i.e., for predefined mission threads) an SOA environment does not necessarily differ signif-

icantly from other distributed environments. It is possible to tailor individual capabilities and ser-

vices, back-end systems, and network and SOA infrastructure to support the needs of specific

mission threads. For example, some organizations are tailoring the SOA deployment architecture

by adding additional hardware (e.g., hardware accelerators for XML parsers) or standing up addi-

tional SOA infrastructure. Taking these kinds of steps enables SOA end-to-end testing to be con-

ducted in ways similar to testing in any distributed environment.

A big selling point of SOA has been the ability to dynamically compose services in response to

specific, emerging situations. Scenarios are commonly presented where personnel check a registry

to determine what services are available and quickly craft and deploy a unique solution perfectly

matched to an emerging problem. However, dynamic composition (and late binding in general)

provides an exceptional challenge for verifying interoperability. The activities to verify syntactic,

semantic, and organizational interoperability must be performed ―on the fly‖ against the specific

scenario presented by the dynamic composition. At best, only testing will only show that each

16

While semantic alignment is being addressed by additional web service standards (e.g., OWL-S, WS-Coordination), these standards are not widely used.

28 | CMU/SEI-2010-TR-011

service conforms to the standards in the system including, ideally, to a common vocabulary (or

vocabularies that can be mapped to each other).

Standardized mechanisms to support the dynamic composition of the semantic, organizational,

and situational aspects of interactions are either immature or simply not available. Therefore, any

dynamically created end-to-end threads must be analyzed to ensure that they do not become error

prone and subject to inconsistencies. Those threads will not have been previously considered in

the testing process, and there is little assurance that they ―interoperate‖ beyond the very basic syn-

tactic level provided by a WSDL specification. It is also useful to capture dynamically created

scenarios for future testing and/or incorporation into future releases.

We recommend that at this point of SOA maturity, compositions should be predefined and tested

for interoperability as well as other quality attributes. Mechanisms should be put in place to as-

sure, to the extent possible, that these predetermined compositions are not compromised by dy-

namic, on-the-fly compositions of services. Dynamic compositions, if allowed, will likely be ―use

at your own risk‖ for the near term.


Rec. 38: Develop a strategy to supports scenario-driven testing of interoperability.

Rec. 39: Develop policies for differential treatment of predefined and dynamic compositions of servic-

es.

Rec. 40: Develop policies for capturing dynamically created threads for future analysis and inclusion

into the collection of predefined threads.

29 | CMU/SEI-2010-TR-011

6 Testing for Security

SOA implementations are susceptible to many of the same security threats that afflict other net-

worked systems. Common vulnerabilities have been found in SOA implementations (both infra-

structure and SOA services), including

denial-of-service attacks on SOAP message handlers and XML parsers

attacks that bypass authentication and authorization mechanisms or spoof identities

attacks that capture usernames and passwords

attacks that execute malicious scripts (often unknown to a benign ―pawn‖)

For more information about these and similar attacks, search the Department of Homeland Securi-

ty’s National Vulnerability Database [34] for SOA, XML, SOAP, and other common SOA terms.

6.1 Thread Modeling and Attack Surface

Maintaining a secure SOA infrastructure and services involves far more than testing and includes

appropriate development and deployment practices, security monitoring during operations, and

maintenance of the security profile during sustainment. However, the focus here on testing for

security must start with models of the threats facing SOA implementations and potential targets of

those threats—that is, on threat modeling and attack surface.

6.1.1 Threat Modeling

Threat Modeling is a technique that is often used to generate security requirements and assess

possible security countermeasures, but it also provides a starting point for security testing. The

STRIDE Threat Model [35] provides six high-level threat categories to identify potential sources

of security failure in systems. The six threat categories in STRIDE, along with an example of an

SOA threat, include:

Spoofing: a malicious party taking on the identity of a legitimate web service requester, such

as by submitting different faked credentials.

Tampering: a malicious party altering the content of data and/or messages, for example by

uploading incorrect data. Tampering attacks normally happen in the context of other forms of

attacks such as spoofing that provide inappropriate access.

Repudiation: a party denying the initiation or authoring of an event or transaction. Repudia-

tion can occur when SOA transactions are not correctly logged.

Information Disclosure: actively gaining access to supposedly secure information, for exam-

ple through lack of (or insufficient) encryption of SOAP messages.

Denial of Service: limiting or eliminating access to a system or resource. Common denial of

service vectors in SOA include SOAP and XML parsers.

Elevation of Privilege: taking on higher privileges than appropriate, such as a normal user

taking on super user or administrative privileges. Again, problems with SOAP message han-

dling have led to such attacks.

30 | CMU/SEI-2010-TR-011

The purpose of a Threat Model is to provide decision support for selecting and locating counter-

measures in the system. Categories of countermeasures to specific sorts of threats are identified in

the first two columns of Table 4.

Table 4: Types of Threats and Typical Countermeasures

Threat Countermeasure Standard

Spoofing Authentication WS-Security

Tampering Signature WS-Security + XML Signature

Repudiation Audit Logging None

Information Disclosure Encryption, Input Validation Encryption: WS-Security + XML Encryption

Input Validation: None

Denial of Service Availability None

Elevation of Privilege Authorization None

The third column of Table 4 identifies common standards that can apply the countermeasures.

Where no widely adopted and implemented industry standard is available, the word None is used

in the table. This does not imply that no standards exist—just that the standard is not widely im-

plemented and adopted, as in the case of the XACML[36] standard for authorization. Many coun-

termeasures can be implemented in various ways with differing degrees of security provided (i.e.,

there is significant flexibility in the standard).

6.1.2 Attack Surface

The application’s attack surface comprises the ways an attacker can find a vector to attack the

application [37,38,39]. Attack Surface is composed of three main elements:

Communication channel—protocols (e.g., HTTP)

Methods—get‖ and ―set‖ methods or URIs (e.g., for SOAP, WSDL, HTTP, and for individual

web service operations)

Data— message payload (e.g., SOAP or XML)

Analysis of the attack surface can be used to locate where threats and countermeasures are appli-

cable and should be considered in the software architecture. This report uses the concept of attack

surface to assist in enumerating web services threats and countermeasures.

6.1.3 Combining Threat Modeling with Attack Surface

Since various forms of threats are possible at the many different points where an SOA implemen-

tation can be attacked, it is useful to combine the concepts of threat modeling and attack surface.

The result is a matrix that identifies the various points where countermeasures may be required.

Different countermeasures can be employed for SOA request and response message exchanges,

and the matrix can be improved by adding this refinement. The resulting matrix is shown in Fig-

ure 3.

31 | CMU/SEI-2010-TR-011

Channel Method Data

Threats Request Response Request Response Request Response

Spoofing

Tampering

Repudiation

Information Disclosure

Denial of Service

Elevation of Privilege

Figure 3: Threats and Attack Surfaces

6.1.4 Use of Threat Modeling with Attack Surface in SOA Testing

Figure 3 identifies many points of vulnerability that must be analyzed during SOA testing. One

can actually imagine two such matrices—one for the SOA infrastructure and another for individu-

al web services. This is a useful approach since both infrastructure and services provide their own

methods and of course employ data. For example, one can imagine an attack aimed at an SOA

registry (typically a capability of the infrastructure) to steal valuable data about the available ser-

vices, as well as a subsequent attack on an individual service that was located via the registry.

This attack also points out another consideration: the strong relationship between the mechanisms

of the infrastructure and the services. In many cases, the mechanisms of the infrastructure must be

tested in concert with those of services. The mechanisms must incorporate a consistent security

model (e.g., standards, standards profile, and security handlers).

6.2 Testing SOA Infrastructure Security

SOA infrastructure is composed of a somewhat variable set of capabilities, including messaging,

data management, security, service registry/repository, policy management, governance, service

orchestration, monitoring, and others.

Many security violations in SOA occur inside the SOA infrastructure, where an attacker slips

through the network and SOA security mechanism on the perimeter and is able to gain unfettered

access to the SOA infrastructure and web services [40]. While a robust testing process will help to

ensure that the security risk of intrusion and compromise is minimized, it cannot replace good

network and SOA security discipline. Several of the specific aspects of SOA infrastructure that

should be tested against attack include

vulnerability testing of SOA infrastructure services against common attacks

correct creation, enablement, and operation of security policies for establishing, using, main-

taining, and deleting accounts

correct security settings for access to infrastructure data, including account information, in-

formation about services in registries and repositories, and information about policies

maintenance of secure posture when multiple SOA infrastructures are connected (federation)

maintenance of secure posture when services are combined into composite services (typical-

ly, orchestrations)

correct infrastructure configuration during installation

monitoring of appropriate and potentially malicious access

auditing/logging capabilities€

32 | CMU/SEI-2010-TR-011

There are many sources of information about SOA security and security controls. The National

Institute of Standards and Technology (NIST) provides very useful advice but does not distin-

guish between testing of infrastructure and individual services [41]. Also, general information

about security testing can be found in the NIST Technical Guide to Information Security Testing

and Assessment [42]. Despite their lack of specific focus on testing SOA infrastructure, these

documents provide an excellent starting point.


Rec. 41: Develop guidelines for testing for security of SOA infrastructure, services it provides or hosts,

and the environment in which it exists based on the level of security required.

6.3 Testing Web Service Security

A key challenge for the application developer is to provide end-to-end security over a possibly

untrustworthy network by threading together loosely coupled, widely distributed, and potentially

black box services [43]. As a result, an application developer must establish trust across a large

number of distributed nodes that can be web servers, application servers, databases, ESBs, service

registries, service repositories, and individual services. Many of these nodes are hidden or un-

known to the application developer because service composition is recursive that is, a service

invoked by the application may invoke other services with their own set of distributed nodes, any

of which could be untrustworthy.

There are several ways to reduce the attack surface of an SOA environment. An obvious way is to

validate that a web service being used by an application is not introducing new resource vulnera-

bilities by scanning the source code for bad practices and malicious intent. There are many tools

available that support source code scanning, and these tools should be incorporated into all securi-

ty governance processes. However, this approach assumes access to source code for web service

implementations.

When source code is available, testers should take advantage of both automated and manual tech-

niques to verify the security footprint of web services. Testing should include verification of

proper use of security mechanisms and standards to manage authentication, authorization,

encryption, and other security aspects

input parameters and attachments to protect against malicious content

proper handling of exception conditions

proper response to known attack vectors

Black box services present a greater problem for a number of reasons. Static analysis techniques

(e.g., to detect potential buffer overflows) cannot be used, and isolating the problems by sandbox-

ing is not always possible. Some obvious types of vulnerabilities may be identified by scanning

service specifications for problems and testing services for various input and load conditions.

Tools that support interface fuzzing are particularly necessary for testing black box services.

Clearly, the attack surface of a composite service or an application using services can be limited

by reducing the number of black-boxed web services that are used. However, this strategy coun-

ters the goal of reusing as much service functionality as possible. In addition, the attack surface of

33 | CMU/SEI-2010-TR-011

the composite or application is itself dynamic. Existing service implementations can change. As a

consequence, late-binding strategies essentially remove the opportunity to completely identify the

attack surface of a web service or an application composed of web services. In these cases, appli-

cation developers are left only with the option of trusting service providers based on their SLAs

and monitoring the service for malicious behavior.


Rec. 42: Consider the entire attack surface in the security testing of all SOA components.

Rec. 43: Develop strategies for testing of services where source code is available and for services for

which source code is unavailable.

Rec. 44: Develop an integrated security strategy that considers the network, the SOA infrastructure,

web services.

6.4 Web Service Verification

Many organizations employ an additional step involving verification/certification of critical prop-

erties prior to deploying the service. The primary goals of web service verification are to analyze

the service for security vulnerabilities, spot potential malicious code and un-patched vulnerabili-

ties, and ensure compliance with security and interoperability standards. Typically, a certification

authority17

performs appropriate checks in these areas and issues a certificate for services that

pass the criteria.

As an alternative to certification through additional testing and onerous checklists, this section

outlines a web service verification process that develops the necessary confidence in a web ser-

vice. The SEI developed this process based on ideas for the U.S. Army. The process (see Figure

4) considers the web service in terms of

its conformance to interface standards

the implementation of the service

monitoring it at runtime

Interface standard checking ensures that the service meets the standards specified by the infra-

structure; we say more about this form of checking in Section 8. Two different strategies are used

for checking the implementation: (1) static code analysis, assisted by tools, where possible, and

(2) various runtime tests such as attempts to break through the service’s security. The third con-

sideration, runtime monitoring, is a key aspect of the process and is used to provide assurance that

the service continues to behave in accordance with the security policy.

This process works in conjunction with testing to maintain the confidentiality, integrity, and

availability of the SOA infrastructure, other web services, back-end systems, end-to-end threads,

and critical data. In this process, a web service is scrutinized from a security and information as-

surance perspective with respect to the following objectives:

17

For the U.S. Army CIO/G6, the goal of this process is the verification of compliance with specific sets of stan-dards and good practices defined by certification criteria.

34 | CMU/SEI-2010-TR-011

Is the web service safe? (i.e., is it safe to deploy it on the SOA infrastructure such that it will

not compromise the integrity of the SOA infrastructure and other components within the ar-

chitecture?)

Is the web service compliant with the SOA infrastructure’s service standards? (i.e., does it

comply with the technology platform and languages, SOA standards, security and interope-

rability standards?)

Does the web service have a well-defined and well-formed service contract (i.e., WSDL)?

Does the web service include source code for review?

Does the web service comply with the service management and governance policies man-

dated by the SOA infrastructure?

Has the service provider provided the necessary service metadata and artifacts?

By forcing service providers to take their services through the verification process, SOA infra-

structure managers obtain a level of assurance on the security of the deployed services. The veri-

fication process should ideally be implemented between the development and deployment phases

of the service life cycle, as part of the overall governance process.

Figure 4: Overview of the Web Service Verification Process


Rec. 45: Web service verification should be used with testing to gain confidence in the confidentiality,

integrity, and availability of the SOA infrastructure, other web services, back-end systems,

end-to-end mission threads, and critical data.

35 | CMU/SEI-2010-TR-011

7 Testing for Other Quality Attributes

Although we have specifically called out interoperability and security, there are many other quali-

ty attributes that must be exhibited and , therefore, which need to be tested. The particular collec-

tion of quality attributes will depend on the organization’s needs; we call out performance and

reliability because they are commonly required and provide examples of testing for quality

attributes.

7.1 Performance

Performance in a system is all about timing. Concerns include execution speed, latency, and the

characteristics of event arrival.

As we discussed previously (Section 5.2.1), testing is allied with the evaluation process by which

components were selected. Testing can thus be performed to ensure that products within the SOA

infrastructure meet the performance criteria for which they should have been evaluated. Infra-

structure components can be tested individually to determine actual values for both performance

and latency, though these results will be of limited value unless the test environment closely mim-

ics the operational environment. 18

As is evident in Figure 5, there are multiple areas where performance can be compromised in the

invocation of even a single web service, making it difficult to establish performance levels on in-

frastructure components like parsers and business process execution engines. This difficulty arises

from the dynamic nature of web service invocation and the effect it has on attributes such as payl-

oad, process complexity, and dependence on other infrastructure components [44]. Performance

testing can also include load and stress testing and can be the source of data for fine tuning to mi-

tigate and address some performance-related bottlenecks.

18

Performance requirements should specify environment context. Load and boundary conditions are critical to proper evaluation of performance.

36 | CMU/SEI-2010-TR-011

Figure 5: Potential Performance Bottleneck Points in a Web Service Invocation

In addition, perspective is important for performance testing, because the testing can be conducted

from the service container and service invoker viewpoints. As an example, Table 5 shows the dif-

ferences in viewing throughput and latency from the service container and service invoker pers-

pectives.

Table 5: Performance Metrics

Service Container Service Invoker

Throughput Typically measured in terms of requests/sec. The average data rate, including latency; usual-

ly measured in data rate/sec.

Latency Time between service request and service re-

sponse

Time taken between service invocation and the

service response

Even so, testing can generate potentially useful measures for the SOA infrastructure. Clearly per-

formance of the infrastructure will affect every thread, and testing can provide insight into the

behavior of end-to-end threads. Testing can also be used to tune the infrastructure, by providing

accurate measures of response time and latency that can be used as data for making engineering

decisions such as the size of a cache or even which of a number of alternate algorithms performs

the best. Infrastructure testing should measure not only overall response time but also time con-

sumed by individual components or services in order to identify correctly the cause of poor res-

ponsiveness.


Rec. 46: Test response time and latency for SOA infrastructure components and component interac-

tions.

Rec. 47: Capture performance data both from the standpoint of the service container and the service

invoker, in realistic scenarios and mission threads, and under varying service, SOA infra-

structure, and network loads.

Both infrastructure services (such as service lookup, data storage, and data translation) and busi-

ness services can be tested to determine whether they meet performance targets in the test envi-

ronment. The assumption underlying this testing is that if they fail to meet their performance tar-

gets in a laboratory-like environment it is unlikely that they will do so in a production

environment. A service will likely behave differently in a realistic setting rather than in a labora-

tory one (due to environmental factors such as server loads, bandwidth limitations, and network

latencies will skew the results). One advantage of such tests, though, is that they may be able to be

used to distinguish between different implementations of the same service. Overall, however, the

best way to establish the adequacy of the performance of a web service is to consider it in the con-

text of the scenarios and mission threads in which it executes.

Evaluation, verification, and monitoring of performance properties of web services involve activi-

ties similar to those for other distributed computing technologies. White box testing can be per-

formed when implementation code is available, but in many cases, services will need to be treated

as if they are black boxes. Similarly, though performance modeling of services is not yet a main-

stream practice, it is recommended for the cases where there is sufficient insight into the service

to construct the model.

37 | CMU/SEI-2010-TR-011

The effect of unpredictable loads is greater when services are shared or are composite services.

For example, if a service has multiple consumers, the increase in load from one consumer will

likely degrade performance to all other consumers. In the case of underperforming composite ser-

vices, it may not be clear whether the lack of performance is due to load on the service or network

or because of a performance bottleneck in one of the services the composite invokes. For compo-

site services, an additional difficulty is that the specific elements of a composite service may not

be known until runtime. This challenge for testing is a result of an SOA benefit—the binding be-

tween the invoking service and the implementation of the services invoked can occur at runtime.

There are several testing tools (some are identified in Section 9) that provide detailed performance

testing for web services. These tools not only test web service performance, but also provide per-

formance testing capabilities for database connections, service registries, messaging infrastruc-

ture, and the like. They also provide the ability to simulate number/types of users and offer distri-

buted load testing.


Rec. 48: Establish the adequacy of the performance of a web service by considering it in the context

of the scenarios and mission threads in which it executes.

Rec. 49: Where possible use models that simulate the service as a basis for performance modeling.

7.2 Reliability

Software reliability is the probability of failure-free software operation for a specified period of

time in a specified environment. The overall reliability of any software component cannot be ade-

quately tested without a proper understanding of its fault model—the model of what can go wrong

and from which the consequences of a fault can be predicted. This is certainly the case with indi-

vidual services, and the overall reliability of an application cannot be tested without a proper un-

derstanding of the fault models of underlying services [45].

However, in most cases this fault model is hidden from the service-oriented application developer.

As a result, the developer often finds it difficult to design tests to stress boundary conditions of

the service through fault injection or other techniques. In addition, it becomes difficult for the ap-

plication developer to find the root causes of problems encountered during reliability testing,

whether the service will recover from a failure, or if the implementation has crashed or just failed

because of specific input.

Another factor that makes evaluation of reliability difficult is the frequent lack of a central coor-

dinator to direct and monitor complex transactions for the application. Participating web services

have the option of whether to implement an internal transaction mechanism. If a transaction me-

chanism is not provided, managing transactions becomes the responsibility of the application.

This can make it difficult to assure transactional integrity.

For example, consider an airline ticket booking web service. By itself, the airline booking service

does not need to be transactional—it either books a ticket or not. However, if an application de-

veloper intends to provide a vacation booking capability by combining airline ticket booking with

38 | CMU/SEI-2010-TR-011

train ticketing and car and hotel booking services, the entire vacation booking capability must be

transactional. A transaction will be considered complete only after all the bookings have been

confirmed. If each individual service is non-transactional, the responsibility is put on the applica-

tion developer to implement transactions. This complicates implementation and testing of compo-

site functionality. In the above example, the airline ticket, car, and hotel booking services would

need to have a compensating operation to cancel reservations to be called in these cases.


Rec. 50: Establish a policy for publishing fault models for individual services and service composi-

tions. The fault models should address common situations such as invalid input or internal

data values, timing conditions (e.g., deadlock, race, and concurrency).

Rec. 51: Develop recommendations for the use of fault models to generate test cases.

39 | CMU/SEI-2010-TR-011

8 Testing for Standards Conformance

SOA implementations depend on the use of standards: Even when the infrastructure is wholly

proprietary, it sets standards to which all services and service consumers must conform. Most im-

plementations, though, are based on web services, and a critical factor in the success of SOA im-

plementations has been the widespread acceptance of standards related to web services and

RESTful services. Testing for compliance to the appropriate standards is necessary to ensure that

basic expectations are met for participation in SOA applications.

The use of even common web service standards (e.g., HTML, XML, WSDL, and SOAP) does not

guarantee interoperability because of vendors’ customized implementation of the standards. For

this reason, the Web Service–Interoperability (WS-I) [6] profiles were developed as a set of non-

proprietary web service specifications which—along with clarifications, refinements, interpreta-

tions and amplifications of those specifications—promote interoperability. Each web service im-

plementation, including COTS implementations, should be checked against WS-I profiles to test

for syntactic interoperability. Note that WS-I also provides a set of testing tools to validate the

conformance to the recommended profiles. Some tools have the added ability to validate confor-

mance to key WS-* standards and assist in viewing test data from web services that use Secure

Sockets Layer (SSL) for encryption. Finally, most organizations have standards over and above

those defined by web services and conformance to these standards must also be confirmed

through testing.

Web services are based on open standards, some of which focus on QoS attributes such as securi-

ty, federation, trust, notification, reliability, transactions, and business activities. In addition, there

are specific standards for some architecturally significant attributes—such as SAML, for some

architecturally significant attributes; SAML is used in security and identity contexts [46]. In this

section, we focus on web services that implement the SOAP protocol over HTTP, with references

to the corresponding technology/standard/protocol for REST where relevant.

Testing a web service and its associated definition for conformance to key standards or protocols

involves steps in the following areas:

Testing and validating the service contract (applicable standard, WSDL). The following

steps are needed to validate the service contract of a web service:

WSDL is well formed.

Implementation conforms to the appropriate WS-I profile.

Authentication standards are followed.

The web service conforms to the SOAP protocol.

The endpoints published in the WSDL are invoked using the web service deployed in the

testing infrastructure.

Where appropriate, the inclusion of web service authentication compliance is checked

for Basic, WS-Security, WS-Digest, and the like.

The WSDL types (what must be communicated) are validated using schemas.

The WSDL document is validated against WS-I Basic Profile 1.0 that provides interope-

rability guidance for a core set of non-proprietary web services specifications, such as

40 | CMU/SEI-2010-TR-011

SOAP, WSDL, and UDDI, along with interoperability-promoting clarifications and

amendments to those specifications.

Validating web service binding and message. The web service is tested for conformance to

the SOAP protocol over HTTP. The following SOAP-over-HTTP patterns are checked:

Request-Response Message Exchange Pattern

Response Message Exchange Pattern

SOAP Web Method Feature

SOAP Action Feature

SOAP binding (validated against the Simple SOAP Binding Profile 1.0 specification

from the WS-I)

SOAP attachments (can be validated using W3C’s SOAP Messages with Attachments

standard)

SOAP over HTTPS (needs to be validated in cases where web services require data and

transport security—i.e., the SSL certificate must be checked for validity)

Validating web service interoperability. Compliance with standards provides confidence that

the web service meets minimal levels of interoperability. The web service is tested for com-

pliance interoperability by ensuring compliance with the following WS-I standards:

WS-I Basic Profile 1.0

Simple SOAP Binding Profile 1.0

W3C’s SOAP Messages with Attachments standard

UDDI version 2.0 XML Schema standard

For compositions of web services, testing for conformance is more problematic. WS-BPEL is

gaining widespread acceptance for web service orchestrations, and several tools exist to parse it

and flag non-conforming use. However, it is possible (and perhaps more common) to build or-

chestrations with no WS-BPEL specification. Thus, conformance checking becomes difficult. For

choreographies, the situation is even less clear. WS-CDL (a W3C product) does not appear to be

widely used, suggesting that most choreographies being built have no specification that can be

machine-parsed and validated for conformance [47].


Rec. 52: Develop an automated strategy for conformance checking of web services, and integrate that

strategy into governance processes.

Rec. 53: Develop automated tools to test for enterprise or organizational-unique conformance re-

quirements as possible.

Rec. 54: Develop a strategy for conformance testing of service compositions.

Rec. 55: Check each web service implementation, including COTS implementations, against the WS-I

profiles to test for syntactic interoperability.

41 | CMU/SEI-2010-TR-011

9 Test-Related Strategies

In this section, we discuss other strategies that can be used in conjunction with testing to achieve

confidence in the SOA system.

Test-driven development and design-by-contract are strategies that developers can use to

reduce the burden on testing through better development.

Effective SOA governance can create policies that, when enforced, simplify the testing

process.

Runtime monitoring can be used to provide data that is used to tune the operational system.

However, that same data can provide testers with valuable insights and assist them in tuning

test cases to match better the reality of the operational system. In addition, performance re-

quirements captured in SLAs can be dynamically tested through the use of runtime monitor-

ing.

Another strategy, assurance cases, can be used to determine what testing is necessary and,

potentially, make regression testing more efficient by limiting the amount of retesting that

has to be done.

9.1 Test-Driven Development

Test-Driven Development (TDD) constructs test cases prior to implementing a capability and then

verifies the capability through the test cases. TDD practice encourages the development of test

cases for small code increments and short iteration cycles. The quality of web services can be im-

proved by using TDD [48]. Service developers can adopt a TDD approach to unit testing web ser-

vices [49][50] during service development, before the services are deployed to the test or product

environment. In a TDD approach, web services can be tested on a locally running server or dep-

loyed in a separate test environment. Also, integrated development environments provide mechan-

isms to perform unit testing of web services. For example, Microsoft Visual Studio .NET allows

the creation of unit tests for web services that can be invoked either on a locally running web

server or an active web server.

During TDD, service developers can test the service for correctness, path coverage, and response

to bad inputs, among other aspects. However, since most testing is performed on non-production

environments, it will not be possible to completely test quality attributes.

Provost discusses three different options for testing web services [49]. The first option uses class

TDD techniques to test directly against the web services interface, similar to how clients of a web

service will invoke it. The second option creates and tests business classes that get called from

lightweight web services. The third option builds a custom XML grammar that allows creation of

new tests without modifying original source code.

The use of TDD testing more effectively enables the integration of the testing process with devel-

opment processes and governance. Ultimately, it may be possible to certify TDD processes such

that a reduced level of post-development verification and validation (V&V) and certification ac-

42 | CMU/SEI-2010-TR-011

tivity is necessary. This can lead to better code quality as well as significant reductions in the cu-

mulative times for development, testing, V&V, and certification activities.

An obvious limitation of TDD is that it only applies to new development; if the SOA strategy is to

create services that are merely wrappers to existing systems, it is too late for TDD to achieve its

full potential. In these cases, testing as described throughout this report will need to be performed.


Rec. 56: Devise a development strategy that includes TDD.

9.2 Design-by-Contract

An emerging paradigm that may ultimately be applied in SOA environments is the design-by-

contract approach. Using design-by-contract tools, developers embed contract assertions in the

form of source code comments. These contract assertions are then translated to instrument code

assertions by the complier. When a contract violation occurs, the instrumentation code creates a

notification that can be acted upon by an infrastructure component or by the invoking code. The

concept behind design-by-contract has been applied in the past with varying degrees of success. It

is out of scope for this report, though, to understand why it has failed to achieve its full potential.


Rec. 57: Investigate the feasibility of design–by-contract approaches.

9.3 Governance Enforcement

Governance, which we characterize as developing and enforcing policy, provides the ability to

manage, control, monitor, and enforce best policies and practices in an SOA deployment.

Governance applied at design time typically tests for compliance with a variety of standards and

best practices (e.g., for compliance with Security Technology Implementation Guides [51] and

coding standards). This governance should also require checks and validation of mandatory arti-

facts and metadata, so that services should be certifiable as compliant with the service on-

boarding process. Such governance also leads to the provision of hooks and touch points to gener-

ate reports that provide information on whether a service has provided the required artifacts and

whether these artifacts are valid and relevant in the desired context.

In cases where organizations group services into portfolios based on common capability or func-

tionality, design time governance testing can ensure that the services assigned to a particular ca-

pability family comply with the mission threads and capabilities that constitute a specific capabili-

ty.

Governance may also be applied at runtime, ensuring that a web service complies with the run-

time policies and provides the tools and technologies to monitor the following service life-cycle

events:

service registration

service discovery

43 | CMU/SEI-2010-TR-011

service delivery

SLA enforcement

security policy enforcement

service availability

service versioning

service logging and auditing

The application of such governance serves as a valuable aid in recognizing unanticipated use sce-

narios and how these scenarios impact service orchestrations, choreography, and security policies.

It also provides a “ring-side view” of service execution in an SOA environment and notifications

when performance, security, and infrastructure thresholds are triggered. Governance can also ap-

ply to runtime monitoring that can shed light on service invocations that can compromise service

availability and can better prepare service developers and infrastructure providers for scalability

and availability.

Runtime data can provide a valuable insight for audit logs and for debugging service exceptions.

The data can be used to review specific mission threads or use cases that trigger exceptions in

certain services or when unanticipated scenarios cause a set of services to be dynamically orches-

trated in a way that violates a security or network policy.


Rec. 58: Runtime monitoring, and particularly runtime governance testing, should be used to evaluate

the effect of unanticipated use scenarios on security and other QoS attributes of the SOA

environment.

9.4 Runtime Monitoring

The category of tools and technologies that provide runtime monitoring capabilities is called En-

terprise Service Management (ESM). This technology can be perceived as the situational aware-

ness enabler in an SOA environment, with the ability to monitor runtime SOA activities and trig-

ger events and notifications when policy is violated or when a software component ceases to

execute. Some of the core capabilities of ESM technology are to

monitor the execution of web services and infrastructure components in an SOA environ-

ment

flag web services that may violate performance or latency thresholds

support systems management tools with up-to-date runtime metrics on SOA infrastructure

components and web services

capture runtime data and generate reports that can be used to resolve disputes related to

SLAs between service providers and service consumers

monitor resource consumption for SOA infrastructure components, web services, and appli-

cations

enforce security policies related to access and binding in the SOA environment

enforce governance policies in the SOA environment

44 | CMU/SEI-2010-TR-011

Because ESM technology is responsible for constant runtime monitoring of SOA infrastructure, it

is deployed at key network gateways or as software agents on the SOA infrastructure to monitor

interactions between web services and SOA infrastructure components (see Figure 6).

Figure 6: Enterprise Service Management (ESM) in an SOA Environment

Additionally, and importantly, the SOA infrastructure can have the capability to monitor perfor-

mance and detect bottlenecks that may be degrading performance. Metrics can be collected and

analyzed as a self-testing capability.


Rec. 59: Develop a strategy for using runtime monitoring to supplement testing and capture data for

analysis and improvement of the SOA infrastructures and web services.

Rec. 60: Runtime monitoring of performance should be used to detect peak performance degradation

or services or components that are bottlenecks.

9.5 Service Level Agreements

SLAs are covenants between a service provider and service consumers that help to obtain a level

of verifiable QoS. They play an import role in SOA because they

provide a standard for service providers to advertise QoS attributes for web services

allow runtime monitoring technologies in an SOA environment to monitor and report con-

formance to web service SLAs

allow service consumers to select services based on SLA requirements, especially in scena-

rios where there are multiple service providers offering the same capability

From a testing perspective, two aspects need to be considered. One consideration is that service

consumers need to specify their QoS requirements in a consistent manner. The second is that ser-

vice providers need to match the needs of these consumers by advertising that their services’

SLAs can be enforced through the service discovery, binding, and invocation life cycle of the in-

frastructure. For testing, service providers collect measurements for comparison to the metrics

specified in the SLA. When SLA violations are detected, appropriate actions are taken such as

dynamic reconfiguration of a service or selection of a different service [52].

There are two key standards for specifying SLAs in a web services environment:

45 | CMU/SEI-2010-TR-011

the Web Service Level Agreement (WSLA) specification, proposed by IBM [53]

the Web Services Agreement Specification (WS-Agreement) specification, proposed by the

Open Grid Forum (OGF) [54]

Based on recent trends, the WS-Agreement specification has seen broader adoption. IBM, BEA,

Microsoft, SAP, Sonic, and VeriSign are working on WS-Policy and WS-PolicyAttachment, two

specifications that address the quality of service aspects of web services SLAs. WS-Policy pro-

vides a specification by which service providers and consumers can use WS-Policy based artifacts

to advertise and consume SLA policies. WS-PolicyAttachment specifically deals with the issue of

attaching policy assertions to web services SLA policies.


Rec. 61: Whenever possible, specify SLAs in a machine-readable format that will allow automatic

monitoring of agreements at runtime.

Rec. 62: Develop monitoring capabilities that can collect and log data relevant to SLAs, and identify

SLA violations when possible

Rec. 63: Develop a strategy for service consumers and providers to provide QoS information in a con-

sistent and standards-driven manner.

Rec. 64: Develop a strategy for SLA creation and validation, oriented toward commercial standards

where possible.

9.6 Assurance Cases

The National Research Council (NRC), in a report entitled Software for Dependable Systems: Suf-

ficient Evidence? [55], finds that even large-scale, end-to-end testing says little about dependabili-

ty for systems where extraordinarily high levels of dependability are required. Similar statements

can be made about other quality attributes such as security and performance: even extensive end-

to-end testing can only demonstrate that there are some conditions under which the systems of

systems overall will do something expected and useful. It is risky to extrapolate to broader con-

clusions about overall system-of-systems behavior on the basis of a set of end-to-end test cases.

For testing to be a credible indicator of overall system-of-systems qualities, the relationship be-

tween testing and the properties being claimed must be explicitly justified. The NRC report re-

commends a well-reasoned argument based upon evidence such as formal proofs, static code

checking, test results, simulation results, and so on.

The SEI is applying the assurance case method to the analysis of end-to-end threads in SOA im-

plementations. The purpose of assurance cases is to provide confidence that a capability will per-

form as expected. An assurance case is similar in nature to a legal case in that it links specific

claims to evidence relevant to the claim and to arguments as to what the evidence supports or does

not support. In an SOA context, evidence (potentially from a test) is linked with arguments about

why the evidence supports specific claims for the SOA implementation (e.g., overall perfor-

mance). Thus, assurance cases can be used to identify the scope of testing after a change has been

made. The uniting of evidence and the argument mitigates the risk of extrapolating from end-to-

end test cases to overall claims about the SOA implementation.

46 | CMU/SEI-2010-TR-011

Assurance cases can augment testing because the case identifies the evidence tests need to provide

and the significance of that evidence in supporting claims about overall system behavior. Further,

assurance cases can help determine whether test results show what they purport to show and

whether the appropriate things have been tested.

Information is available from the SEI about the applicability of assurance cases to dependability

[56], security [57], and survivability [58].


Rec. 65: Develop a strategy that supports the development of well-reasoned arguments about the

quality of testing for critical mission threads.

47 | CMU/SEI-2010-TR-011

10 Summary

Testing SOA implementations is challenging for various reasons. For example, services are often

outside the control of the organization consuming the service (i.e., service developers are inde-

pendent from service providers and service consumers), leading to potential mismatches and mi-

sunderstandings between parties. Also, SOA implementations are often highly dynamic, with fre-

quently changing services and service consumers and varying load on services, SOA

infrastructure, and the underlying network. Consequently, it is normally not possible to replicate

all possible configurations and loads during the testing process. What is possible is to identify and

maintain a set of configurations that are deemed important and use them as the basis for defining

the test environments.

We suggest in this report that testing SOA implementations needs to account for elements that

reflect functional, non-functional (as perceived through the quality attributes of the services), and

conformance aspects. By devising a strategy for testing the SOA infrastructure, web services (in-

dividual and composite services), and end-to-end threads, those responsible for testing the SOA

implementation can more comprehensively perform unit, integration, and system-level testing

(also known as dynamic testing). Aiding that effort, which is bound to be fraught with many chal-

lenges, are tools that can automate testing and web service verification processes.

In discussing the aspects, elements, and processes associated with SOA implementation testing,

we make many recommendations, each phrased in the form of an assertion (a ―do‖ statement).

Our recommendations stress a few fundamental principles, such as:

It is important to view testing in a strategic way, recognizing that the SOA implementation is

meant to serve business and mission goals.

A testing strategy should not ignore the complexity of SOA implementations that can arise

from the absence of full information about services and interfaces, rapid service upgrade

cycles, and other factors.

A testing strategy is incomplete if it leaves out the testing of end-to-end threads.

In addition to making recommendations for solid practice in SOA implementation testing, this

report also points to areas where further examination is warranted. In particular, the use of tools to

automate testing and the development of more efficient web services verification processes stand

out. Automation in testing, for instance, can make regression testing timelier, which can more

readily meet the needs brought about by the frequency of service updates and the implications for

other consumers of a change to any one service. Efficient web service verification, while filling

security and information assurance needs, can allow new and upgraded services to be incorpo-

rated with confidence in less time. This can allow services to be made available with the same

agility in which they are developed.

48 | CMU/SEI-2010-TR-011

49 | CMU/SEI-2010-TR-011

Appendix A List of Acronyms Used

Acronym Description

ATO Authority to Operate

BPEL Business Process Execution Language

CIO/G6 Chief Information Officer/G6

COTS Commercial off-the-Shelf

ESB Enterprise Service Bus

ESM Enterprise Service Management

GML Geography Markup Language

GOTS Government Off-The-Shelf

HTML Hyper Text Markup Language

HTTP Hypertext Transport Protocol

HTTPS Hyper Text Transport Protocol Secure

NIST National Institute of Standards and Technology

NRC National Research Council

OASIS Organization for the Advancement of Structured Information Standards

OSI Open Systems Interconnection

OSIRM Open Systems Interconnection (OSI) Basic Reference Model

OWL Ontology Web Language

OWL-S Formerly DAML-S; is the Ontology Web Language for Services

QoS Quality of Service

RDF Resource Description Framework

REST Representational State Transfer

RTSS Research, Technology, and System Solutions (RTSS)

SAML Security Assertion Markup Language

SEI Software Engineering Institute

SLA Service Level Agreement

SOA Service-Oriented Architecture

SOAP Simple Object Access Protocol

SSL Secure Sockets Layer

TDD Test-Driven Development

TST Time Sensitive Targeting

UCORE Universal Core

50 | CMU/SEI-2010-TR-011

UDDI Universal Description Discovery and Integration

V&V Verification and validation

W3C World Wide Web Consortium

WS-I Web Services Interoperability Organization

WSDL Web Service Description Language

WSMO Web Service Modeling Ontology

WS-BPEL Web Services Business Process Execution Language

XML eXtensible Markup Language

51 | CMU/SEI-2010-TR-011

Appendix B Consolidated List of Recommendations

Rec. 1: Develop an SOA test strategy that accounts for SOA infrastructure elements, web services

(individual and composites), and end-to-end threads.

Rec. 2: Establish guidelines for testing the service before it is ready for use either by the service

consumers or the service integrator.

Rec. 3: Establish clear lines of testing and customer support responsibility that allow for distinctions

between the roles of service developers and service providers.

Rec. 4: Develop governance processes that support service consumers in the identification of use

cases and the tests necessary to achieve appropriate assurance about performance of the

service within those use cases.

Rec. 5: Develop guidelines for testing composites of various types, including composites that imple-

ment capabilities supporting pre-defined mission threads and ad hoc composites that reflect

attempts to address emerging needs.

Rec. 6: Develop guidelines for testing composites employing the range of composition mechanisms

expected (e.g., WS-BPEL defined, application-embedded composites, WS-CDL)

Rec. 7: Develop guidelines and governance processes for testing/verification of new and revised

infrastructure capabilities, including notification of users of infrastructure changes and trig-

gers for retesting.

Rec. 8: Develop policies for the type and level of testing support provided by the infrastructure pro-

vider to the service provider or integrator.

Rec. 9: Identify the focus, expectations, and limitations of third-party testing/certification activities.

Rec. 10: Develop policy clearly delineating the forms of testing performed according to SOA roles.

Rec. 11: Provide developers with a fully outfitted test environment for early testing of services and

service orchestrations; provide this environment to testing organizations, too, for performing

certification activities.

Rec. 12: Develop strategies for testing of the service registration mechanism.

Rec. 13: Develop tests to determine whether authorized service consumers can find services based

on syntactic or semantic approaches.

Rec. 14: Develop tests that reveal whether all appropriate service providers and consumers are noti-

fied when a new version of a service is registered with the infrastructure or when service le-

vels are violated.

Rec. 15: Develop a testing strategy for service monitoring capabilities.

Rec. 16: Develop a testing strategy for service virtualization features.

Rec. 17: Provide support for service mocking, including mocking of services on remote platforms and

infrastructures.

Rec. 18: Integrate service mocking into the development and testing strategies.

Rec. 19: Develop guidelines for the type of faults that services and service compositions must be

tested for.

Rec. 20: Formal agreements should be in place with data providers to identify test data sets and test

interfaces.

52 | CMU/SEI-2010-TR-011

Rec. 21: Establish baselines for services, compositions, and end-to-end threads.

Rec. 22: Establish regression testing triggers for each.

Rec. 23: Establish a regression testing sandbox fitted with appropriate testing and analysis tools to

automate regression testing to the degree possible.

Rec. 24: Use approaches such as assurance cases to identify when additional regression testing is

needed.

Rec. 25: Develop a strategy for testing at each of the layers of the SOA interoperation stack.

Rec. 26: Instrument test instances to help identify the sources of failures.

Rec. 27: Perform regression testing to identify the impacts of changes on services, nodes and com-

ponents along the pathway that is exercised.

Rec. 28: Develop a strategy for identifying the important threads in an end-to-end threads and deco-

rating those threads with both functional and QoS expectations.

Rec. 29: Develop test cases for critical threads that have been identified.

Rec. 30 For certain types of services (e.g., public web services on the internet) where the actual op-

erating context (e.g., expected load and usage, level of security required, etc.) is unknown

until the service is actually being used, it may be necessary to adopt an incremental ap-

proach in which functionality is fielded and the system is then adjusted to meet QoS goals.

Rec. 31: Develop a strategy for identifying and testing likely dynamically composed threads.

Rec. 32: Implement “non-interference” strategies such that other threads cannot compromise function-

ing or QoS in the rest of the end-to-end thread..

Rec. 33: Develop a strategy for cross-site and cross-organizational collaboration to identify test con-

text and data loads.

Rec. 34: Develop a strategy for cross-site and cross-organizational verification of changes in back-end

systems and capturing and analysis of test results.

Rec. 35: Develop a strategy to identify and test the capabilities of SOA infrastructures that are needed

to federate the infrastructure.

Rec. 36: Develop a list of interoperability standards that services must comply with, and consider of-

fering an interoperability compliance check as a service to developers.

Rec. 37: Develop a list of data models that services must use and consider offering a compliance

check as a service to developers.

Rec. 38: Develop a strategy to supports scenario-driven testing of interoperability.

Rec. 39: Develop policies for differential treatment of predefined and dynamic compositions of servic-

es.

Rec. 40: Develop policies for capturing dynamically created threads for future analysis and inclusion

into the collection of predefined threads.

Rec. 41: Develop guidelines for testing for security of SOA infrastructure, services it provides or hosts,

and the environment in which it exists based on the level of security required.

Rec. 42: Consider the entire attack surface in the security testing of all SOA components.

Rec. 43: Develop strategies for testing of services where source code is available and for services for

which source code is unavailable.

Rec. 44: Develop an integrated security strategy that considers the network, the SOA infrastructure,

web services.

53 | CMU/SEI-2010-TR-011

Rec. 45: Web service verification should be used with testing to gain confidence in the confidentiality,

integrity, and availability of the SOA infrastructure, other web services, back-end systems,

end-to-end mission threads, and critical data.

Rec. 46: Test response time and latency for SOA infrastructure components and component interac-

tions.

Rec. 47: Capture performance data both from the standpoint of the service container and the service

invoker, in realistic scenarios and mission threads, and under varying service, SOA infra-

structure, and network loads.

Rec. 48: Establish the adequacy of the performance of a web service by considering it in the context

of the scenarios and mission threads in which it executes.

Rec. 49: Where possible use models that simulate the service as a basis for performance modeling.

Rec. 50: Establish a policy for publishing fault models for individual services and service composi-

tions. The fault models should address common situations such as invalid input or internal

data values, timing conditions (e.g., deadlock, race, and concurrency).

Rec. 51: Develop recommendations for the use of fault models to generate test cases.

Rec. 52: Develop an automated strategy for conformance checking of web services, and integrate that

strategy into governance processes.

Rec. 53: Develop automated tools to test for enterprise or organizational-unique conformance re-

quirements as possible.

Rec. 54: Develop a strategy for conformance testing of service compositions.

Rec. 55: Check each web service implementation, including COTS implementations, against the WS-I

profiles to test for syntactic interoperability.

Rec. 56: Devise a development strategy that includes TDD.

Rec. 57: Investigate the feasibility of design–by-contract approaches.

Rec. 58: Runtime monitoring, and particularly runtime governance testing, should be used to evaluate

the effect of unanticipated use scenarios on security and other QoS attributes of the SOA

environment.

Rec. 59: Develop a strategy for using runtime monitoring to supplement testing and capture data for

analysis and improvement of the SOA infrastructures and web services.

Rec. 60: Runtime monitoring of performance should be used to detect peak performance degradation

or services or components that are bottlenecks.

Rec. 61: Whenever possible, specify SLAs in a machine-readable format that will allow automatic

monitoring of agreements at runtime.

Rec. 62: Develop monitoring capabilities that can collect and log data relevant to SLAs, and identify

SLA violations when possible.

Rec. 63: Develop a strategy for service consumers and providers to provide QoS information in a con-

sistent and standards-driven manner.

Rec. 64: Develop a strategy for SLA creation and validation, oriented toward commercial standards

where possible.

Rec. 65: Develop a strategy that supports the development of well-reasoned arguments about the

quality of testing for critical mission threads.

54 | CMU/SEI-2010-TR-011

55 | CMU/SEI-2010-TR-011

Appendix C Key Attributes for Testing Web Services

Web Service Inspection

1. SOAP 1.1 & 1.2 Support

2. WSDL Viewer and Validation

3. XML Schema Inspection

4. XML Table Inspection

5. Web Service Form Editor

6. Web Service Overview

7. SOAP Monitoring

Web Service Invocation

1. Automatic Request Generation

2. Endpoint Management

3. WS-Security Standard Support

4. WS-Attachment Support (MTOM, SOAP Attachment, Inline)

5. Custom HTTP header for REST

6. Raw Messages

7. Web Service Form Editor

8. Web Service Tree Editor

9. WS-Security Support

10. Web Service Recording

11. WSDL Validation

Functional Testing

1. WSDL Coverage

2. Request/Response Coverage

3. Message Assertion

4. Test Refactoring

5. Test Refactoring

6. Drag and Drop Test Creation

7. Message Pretty Printing

8. Coding Free Test Assertion

9. Running of Multiple Tests

10. Test Logs

11. Test Configuration

12. Easy Content Transfer

13. Data Source Driven Tests

56 | CMU/SEI-2010-TR-011

Functional Testing, continued

1. Data Collection

2. MockResponse

3. Maven Integration

4. Standalone Server Runners

5. Scripting Support

6. Scripting Libraries

7. Requirements Management

8. Reporting

9. Integrated Reporting

10. Form Based input for easy manual testing

11. Tree Based input for easy manual testing

12. Create Test from Web Service Recordings


14. WS-I Integration

15. Web Service Recording

Load Testing

1. Rapid Load Tests from Functional Tests

2. Configurable Load Strategies

3. LoadTest Assertions

4. Real Time Statistics

5. Real Time Diagrams

6. Statistics Exporting

7. Performance Monitoring

8. Run from command line and Maven

Web Service Simulation: MockServices

1. Create Automatic MockService From WSDL

2. Add Operations to MockService

3. Create Custom Responses

4. Multiple Dispatching Options including Scripts


6. WSDL Publishing

7. SSL Support

8. WSDL Coverage

9. Run from command line and Maven

57 | CMU/SEI-2010-TR-011

Web Service Development and Validation

1. Generate Server and Client Code

2. Generated XML Bindings

3. Command Line Support

4. Validate Web Service Definitions

5. Validate Request and Response Bodies

6. IDE Integration

58 | CMU/SEI-2010-TR-011

59 | CMU/SEI-2010-TR-011

Appendix D Testing Process Preconditions and Deliverables

Testing of an SOA implementation should begin early and occur often, yet should not discourage

engineers from achieving the desired agility often cited as a primary goal of SOA. This represents

a potential conflict between achieving agility and performing rigorous testing. Many organiza-

tions are addressing this conflict by employing multi-phased processes where individual services

must overcome low entry barriers for initial, discovery-oriented, phases, followed by increasingly

higher barriers in subsequent phases leading ultimately to widespread deployment.

Preconditions for Testing Process

We strongly endorse this phased strategy. Ultimately, however, formal testing for making dep-

loyment decisions must begin. We suggest the following information be made available to testers

prior to the initiation of such testing. Subsets of this information may make up the core of the en-

try barriers for earlier testing phases:

For Web Services and Composites:

Architectural and design documentation in accordance with the organization’s standards and

guidelines. Information about documenting software architectures can be found in Docu-

menting Software Architectures: Views and Beyond [59].

Service metadata: information about the provider, developer, versions and releases, technol-

ogy dependencies, platforms, security classification/mission access categories, data and net-

work access. This metadata should be incorporated into the SLA.

WSDL specifications

Service source code (if available)

SLAs capturing

Information necessary to deploy the service: ports, protocols, scripts, guidance and con-

straints

Information necessary to access the service

Information about the semantics of the service: business rules, behaviors, use cases, and

sequencing

Information about runtime dependencies: runtime environment and dependencies on

other applications and data sources, etc.

Information about operations: contact points, change management, versions and dep-

loyment, support, fault reporting, etc.

Information about QoS provided (availability, response time, throughput, fault tolerance,

etc.)

Information about security (policies, authority to operate (ATO) certification authorities,

criteria and restrictions, vulnerabilities, monitoring, etc.)

Constraints on configuration, deployment, execution of the service

Information about testing that has been accomplished (type, parties, setup, tool support,

results, etc.)

60 | CMU/SEI-2010-TR-011

For SOA Infrastructure

Information analogous to that required for web services, plus:

Configuration information and data for the various infrastructure components

Licenses and agreements with providers of individual capabilities

For end-to-end threads

information analogous to that provided for web services

metadata about the thread

code controlling orchestration (e.g., BPEL for business process threads) of the thread, if

available

documents analogous to SLAs, but presented from the perspective of the mission thread

documents capturing requirements and other expectations for the thread

Deliverables from the Testing Effort

The IEEE Standard for Software Test Documentation [60] provides a starting point for identify-

ing deliverables for any testing effort. SOA-specific implementation guidance is as follows:

Documents related to test specifications

Test design specifications identifying the approach, test procedures and cases, and pass/fail

criteria. An SOA test design specification needs to clearly identify unique features of SOA

testing that affect the testing approach, tasks, and environment. The testing approach should

identify appropriate strategies for testing the SOA infrastructure, services with and without

source code availability, SOA services deployed on ―local‖ infrastructures and ―remote‖ in-

frastructures, and end-to-end testing of predefined and dynamically composed mission

threads. The desired characteristics of the testing environment and the responsibilities of all

participants in that environment (e.g., loading of test data, capturing of metrics) should be

clearly defined.

Test case specifications identifying the input, output, contextual data, and constraints on pro-

cedures. SOA test case specifications should include flexibility to incorporate automated

testing techniques such as fuzzing that produce multiple executions based on variations of

input parameters and attachments. In addition, test case specifications should address desired

quality of service attributes; pay particular attention to the hardware and software configura-

tions; and identify appropriate network, SOA environment, and service loads at the time of

testing.

Test procedure specifications identifying steps to operate the environment and run the tests.

SOA test procedures are likely to be complex due to the distributed and dynamic nature of

SOA environments. There may be extensive procedures for establishing the environment

context prior to testing (e.g., to load appropriate data in remote databases), for executing

tests, and for capturing the results of the test. For service and end-to-end testing, verification

of a test may require access to information on remote machines and back end data stores.

61 | CMU/SEI-2010-TR-011

Documents related to test reporting:

Test item transmittal reports identifying the communication mechanism between implemen-

tation and testing groups. The transmittal reports should reflect the range of involved parties

(i.e., for SOA infrastructure, individual services, composites, end-to-end threads).

Test log records of what occurred. Test logs should capture to the extent possible the

exact environment context at the point of the test. This includes, loads on networks, SOA in-

frastructure and services identification and version records, and specific hardware and soft-

ware configurations and versions. This information will be essential for analyzing test results

and anomalous events that occur. Logs may also have to address issues such as lack of uni-

versal time across the distributed environment (i.e., inconsistent timestamps).

Test incident reports that record incidents that require further investigation. Incident reports

are often given inadequate attention even in traditional development. This leads to difficulty

in isolating errors and reproducing problems. For SOA implementations, failure to capture

complete descriptions of problems and the context in which they occur may be even more

damaging due to the distributed nature of SOA applications. Test summary reports summa-

rizing the testing activity. These reports may contain findings and recommendations about all

elements of the SOA implementation.

62 | CMU/SEI-2010-TR-011

63 | CMU/SEI-2010-TR-011

References

URLs are valid as of the publication date of this document.

[1] G. A. Lewis, E. Morris, S. Simanta, and L. Wrage, "Common Misconceptions about

Service-Oriented Architecture," in Proceedings of the Sixth International IEEE

Conference on Commercial-off-the-Shelf (COTS)-Based Software Systems, Banff,

Alberta, Canada, 2007, pp. 27-30.

[2] HTTP. (2003) World Wide Web Consortium. HTTP - Hypertext Transfer Protocol.

[Online]. http://www.w3.org/Protocols/

[3] SOAP. (2003) World Wide Web Consortium. HTTP - Hypertext Transfer Protocol.

[Online]. http://www.w3.org/Protocols/

[4] WSDL. (2005, Aug.) Web Services Description Language (WSDL) Version 2.0 Part 1:

Core Language. W3C Working Draft. [Online]. http://www.w3.org/TR/wsdl20/

[5] UDDI . (2005) Organization for the Advancement of Structured Information Standards.

OASIS UDDI. [Online]. http://www.uddi.org/

[6] C. Kaner, J. Falk, and H. Q. Nguyen, Testing Computer Software, 2nd ed. Hoboken, NJ,

USA: John Wiley & Sons, Inc., 1999.

[7] J. A. Whittaker, "What Is Software Testing? And Why Is It So Hard? ," IEEE Software,

vol. 17, pp. 70-79, 2000.

[8] L. O'Brien, L. Bass, and P. Merson, "Quality Attributes and Service-Oriented

Architectures," Technical Note CMU/SEI-2005-TN-014, 2005. [Online].

http://www.sei.cmu.edu/library/reports/abstracts/05tn014.cfm

[9] (2009) World Wide Web Consortium. [Online]. http://www.w3.org/

[10] Web Services Interoperability Organization. [Online]. http://www.ws-i.org/

[11] Organization for the Advancement of Structured Information Standards (OASIS ).

[Online]. http://www.oasis-open.org/home/index.php

[12] (JSAWG), Joint Security Architecture Working Group, "SOA Security Requirements,

Working Group Report v 0.11- 1/14/08," 2008.

[13] F. Hueppi, L. Wrage, and G. A. Lewis, "T-Check in Technologies for Interoperability:

Business Process Management in a Web Services Context," Technical Note CMU/SEI-

2008-TN-005, 2008. [Online].


http://www.w3.org/Protocols/

http://www.w3.org/Protocols/

http://www.w3.org/TR/wsdl20/

http://www.uddi.org/


http://www.w3.org/

http://www.ws-i.org/

http://www.oasis-open.org/home/index.php


64 | CMU/SEI-2010-TR-011

[14] C. Peltz, "Web services orchestration and choreography," Computer, vol. 36, pp. 46-52,

2003.

[15] M. Rosen. (2008, Apr.) www.bptrends.com. [Online].

http://docs.google.com/gview?a=v&q=cache:QdG8l6xlZEwJ:www.bptrends.com/public

ationfiles/04-08-COL-BPMandSOA-OrchestrationorChoreography-%25200804-Ro-

sen%2520v01%2520_MR_final.doc.pdf+SOA+service+orchestration+verses+choreogra

phy&hl=en&gl=us&sig=AFQjCNG1eN

[16] R. A. Paul, "DoD towards software services," in WORDS '05: Proceedings of the 10th

IEEE International Workshop on Object-Oriented Real-Time Dependable Systems, 2005,

pp. 3-6.

[17] K. C. Morris and D. Flater, "Standards-based Software Testing in a Net-Centric World,"

in Proceedings of the Ninth International Workshop on Software Technology and

Engineering Practice (STEP 1999), Pittsburgh, 1999, pp. 115-122.

[18] REST. (2010) Wikimedia Foundation. Representational State Transfer. [Online].

http://en.wikipedia.org/wiki/Representational_State_Transfer

[19] WS-Notificatino. (2010) Organization for the Advancement of Structured Information

Standards. OASIS Web Services Notifi-cation (WSN) TC. [Online]. http://www.oasis-

open.org/committees/tc_home.php?wg_abbrev=wsn

[20] WS-Trust. (2007) Organization for the Advancement of Structured Information

Standards. WS-Trust 1.3. OASIS Standard. [Online]. http://docs.oasis-open.org/ws-

sx/ws-trust/200512/ws-trust-1.3-os.html

[21] M. Penta, M. Bruno, G. Esposito, V. Mazza, and G. Canfora, "Web Services Regression

Testing," in Test and Analysis of Web Services. Heidelberg: Springer Berlin, 2007.

[22] B. Woolf, "Streamline SOA Development using Service Mocks," in developerWorks.

IBM, 2005, vol. 2009.

[23] U. Godage, "Mock Web services with Apache Synapse to develop and test Web

services," in developerWorks | SOA and Web services. IBM, 2008, vol. 2009.

[24] B. Lublinsky, "Mocking Web Services," InfoQ, 2008.

[25] L. F. de Almeida and S. R. Vergilio, "Exploring Perturbation Based Testing for Web

Services," in International Conference on Web Services ( ICWS '06), 2006, pp. 717-726.

[26] M. G. Fugini, B. Pernici, and F. Ramoni, "Quality Analysis of Composed Services

through Fault Injection," in Business Process Management Workshops. Heidelberg:

Springer Berlin, 2008, vol. 4928, pp. 245-256.

[27] X. Wuzhi, J. Offutt, and L. Juan, "Testing Web services by XML perturbation," in

http://www.bptrends.com

http://docs.google.com/gview?a=v&q=cache:QdG8l6xlZEwJ:www.bptrends.com/public

http://en.wikipedia.org/wiki/Representational_State_Transfer

http://www.oasis-open.org/committees/tc_home.php?wg_abbrev=wsn



http://docs.oasis-open.org/ws-sx/ws-trust/200512/ws-trust-1.3-os.html



65 | CMU/SEI-2010-TR-011

Software Reliability Engineering: Proceedings of the 16th IEEE International

Symposium (ISSRE 2005), Chicago, 2005, pp. 257-266.

[28] Y. Sikri, "End-to-End Testing for SOA-Based Systems," MSDN Architecture Center,

vol. 2008, 2007.

[29] M. Gagliard and W. Wood, "System of Systems Architecture Evaluation with Concurrent

Development," in Third SEI Software Architecture Technology User Network Workshop

(SATURN 2007), Pittsburgh, 2007.

[30] X. Bai, C. P. Lam, and H. Li, "An Approach to Generate the Thin-Threads from the

UML Diagrams," in 28th Annual International Computer Software and Applications

Conference (COMPSAC'04), 2004, pp. 546-552.

[31] N. Raza, A. Nadeem, and M. Z. Iqbal, "An Automated Approach to System Testing

Based on Scenarios and Operations Contracts," in Seventh International Conference on

Quality Software (QSIC 2007), 2007, pp. 256-261.

[32] W. T. Tsai, C. Fan, Z. Cao, B. Xiao, and H. Huang, "A Scenario-Based Service-Oriented

Rapid Multi-Agent Distributed Modeling and Simulation Framework for SoS/SOA and

Its Applications," in Foundations ’04: A Workshop for VV&A in the 21st Century, 2004.

[33] WS-BPEL. (2007) Organization for the Advancement of Structured Information

Standards. Web Services Business Process Execution Standard Version 2.0 . [Online].

http://docs.oasis-open.org/wsbpel/2.0/OS/wsbpel-v2.0-OS.html

[34] Department of Homeland Security. National Vulnerability Database. [Online].

http://nvd.nist.gov/

[35] Microsoft Corporation. (2005) [Online]. http://msdn.microsoft.com/en-

us/library/ms954176.aspx

[36] OASIS. (2005, Feb.) [Online]. http://docs.oasis-open.org/xacml/2.0/access_control-

xacml-2.0-core-spec-os.pdf

[37] M. Howard, "Fending Off Future Attacks by Reducing Attack Surface," 2003.

[38] P. K. Manadhata and J. M. Wing, "Measuring a System's Attack Surface," Carnegie

Mellon University, Technical Report CMU-CS-04-102, 2004.

[39] P. K. Manadhata, K. Tan, R. A. Maxion, and J. M. Wing, "An Approach to Measuring A

System’s Attack Surface," Carnegie Mellon University CMU-CS-07-146, 2007.

[Online]. http://reports-archive.adm.cs.cmu.edu/anon/2007/CMU-CS-07-146.pdf

[40] M. Hafner and R. Breu, Security Engineering for Service-Oriented Architectures. Berlin,

Germany: Springer, 2009.

http://docs.oasis-open.org/wsbpel/2.0/OS/wsbpel-v2.0-OS.html

http://nvd.nist.gov/

http://msdn.microsoft.com/en-us/library/ms954176.aspx



http://docs.oasis-open.org/xacml/2.0/access_control-xacml-2.0-core-spec-os.pdf



http://reports-archive.adm.cs.cmu.edu/anon/2007/CMU-CS-07-146.pdf

66 | CMU/SEI-2010-TR-011

[41] A. Singhal, T. Winograd, and K. Scarefone. (2007, Aug.) Guide to Secure Web Services.

[Online]. http://csrc.nist.gov/publications/nistpubs/800-95/SP800-95.pdf

[42] K. Scarfone, M. Souppaya, A. Cody, and A. Orebaugh. (2008, Sep.) Technical Guide to

Information Security Testing and Assessment. [Online].

http://csrc.nist.gov/publications/nistpubs/800-115/SP800-115.pdf

[43] A. Barbir, C. Hobbs, E. Bertino, F. Hirsch, and L. Martino, "Challenges of Testing Web

Services and Security in SOA Implementations," in Test and Analysis of Web Services.

Heidelberg: Springer Berlin, 2007, pp. 395-440.

[44] I. Crnkovic, M. Larsson, and O. Preiss, "Concerning Predictability in Dependable

Component-Based Systems: Classification of Quality Attributes," Architecting

Dependable Systems, vol. III, pp. 257-278, 2005.

[45] V. Cortellessa and V. Grassi, "Reliability Modeling and Analysis of Service-Oriented

Architectures," in Test and Analysis of Web Services. Heidelberg: Springer Berlin, 2007,

pp. 339-362.

[46] SAML. (2010) Wikimedia Foundation, Security Assertion Markup Language. [Online].

http://en.wikipedia.org/wiki/Security_Assertion_Markup_Language

[47] WS-CDL. (2004) Worldwide Web Consortium. Web Services Choreography Description

Language Version 1.0. [Online]. http://www.w3.org/TR/2004/WD-ws-cdl-10-20041217/

[48] K. Beck, Test Driven Development: By Example. Addison-Wesley Professional, , 2002.

[49] P. Provost, "Test-Driven Development and Web Services," Geek Noise, 2009.

[50] D. Vines, "Test-driven development in an SOA environment: Part 1: Testing data maps,"

in developerWorks WebSphere | SOA and Web Services. IBM, 2008., vol. 2009.

[51] Security Technology Implementation Guides. [Online].

http://iase.disa.mil/stigs/index.html

[52] P. Bianco, G. A. Lewis, and P. Merson, "Service Level Agreements in Service-Oriented

Architecture Environment," Technical Note CMU/SEI-2008-TN-021, 2008. [Online].

http://www.sei.cmu.edu/library/abstracts/reports/08tn021.cfm

[53] H. Ludwig, A. Keller, A. Dan, R. King, and R. Franck, "Web Service Level Agreement

(WSLA) Language Specification, Version 1.0," 2003. [Online].

http://www.research.ibm.com/wsla/WSLASpecV1-20030128.pdf

[54] A. Andrieux, et al., "Web Services Agreement Specification (WS-Agreement)," 2007.

[Online]. http://www.ogf.org/documents/GFD.107.pdf

[55] D. Jackson, M. Thomas, and L. I. Millett, Software for Dependable Systems: Sufficient



http://en.wikipedia.org/wiki/Security_Assertion_Markup_Language

http://www.w3.org/TR/2004/WD-ws-cdl-10-20041217/

http://iase.disa.mil/stigs/index.html


http://www.research.ibm.com/wsla/WSLASpecV1-20030128.pdf

http://www.ogf.org/documents/GFD.107.pdf

67 | CMU/SEI-2010-TR-011

Evidence?. The National Academy Press, 2007.

[56] J. Goodenough, C. Weinstock, and J. J. Hudak, "Dependability Cases," Technical Note

CMU/SEI-2004-TN-016, 2004. [Online].


[57] J. Goodenough, H. Lipson, and C. Weinstock. (2008) Build Security IN. [Online].

https://buildsecurityin.us-cert.gov/daisy/bsi/articles/knowledge/assurance/643-BSI.html

[58] R. Ellison, J. Goodenough, C. Weinstock, and C. Woody, "Survivability Assurance for

System of Systems," Pittsburgh, Technical Report CMU/SEI-2008-TR-008, 2008.

[Online]. http://www.sei.cmu.edu/library/abstracts/reports/08tr008.cfm

[59] P. Clements, et al., Documenting Software Architectures: Views and Beyond. Addison-

Wesley Professional, 2002.

[60] IEEE, IEEE Standard for Software Test Documentation. vol. 829. New York: IEEE

Computer Society, 1998.

[61] M. W. Maier, "Architecting principles for systems-of-systems," Systems Engineering,

vol. 1, pp. 267-284, 1999.

[62] P. Donham. (2007) Aberdeen Group Company Web Site. [Online].

http://www.aberdeen.com/summary/report/benchmark/4117-RA-soa-web-services.asp

[63] Software AG. (2008) Software AG web site. [Online].

http://www.softwareag.com/Corporate/res/

[64] L. F. a. V. S. R. s. l. de Almeida, "Exploring Perturbation Based Testing for Web

Services," in International Conference on Web Services ( ICWS '06), 2006, pp. 717-726.

[65] P. K. Manadhata, K. Tan, R. A. Maxion, and J. M. Wing, "An Approach to Measuring A

System's Attack Surface (CMU-CS-07-146)," Pittsburgh, Technical Report, 2007.

[66] G. Canfora and M. Di Penta, "Testing services and service-centric systems: challenges

and opportunities," IT Professional, vol. 8, pp. 10-17, 2006.

[67] K. M. Kumar, A. S. Das, and S. Padmanabhuni, "WS-I Basic Profile: a practitioner's

view," in Proceedings of the IEEE International Conference on Web Services, 2004, pp.

17-24.

[68] G. A. Lewis, E. Morris, S. Simanta, and L. Wrage, "Why Standards Are Not Enough to

Guarantee End-to-End Interoperability," in Proceedings of the Seventh International

Conference on Composition-Based Software Systems (ICCBSS 2008), 2008, pp. 164-173.

[69] J. Grundy, J. Hosking, L. Li, and N. Liu, "Performance engineering of service

compositions," in Proceedings of the 2006 international workshop on Service-oriented


https://buildsecurityin.us-cert.gov/daisy/bsi/articles/knowledge/assurance/643-BSI.html

http://www.sei.cmu.edu/library/abstracts/reports/08tr008.cfm

http://www.aberdeen.com/summary/report/benchmark/4117-RA-soa-web-services.asp

http://www.softwareag.com/Corporate/res/

68 | CMU/SEI-2010-TR-011

software engineering, 2006, pp. 26-32.

[70] M. R. Barbacci, et al., "Quality Attribute Workshops (QAWs), Third Edition,"

Pittsburgh, Technical Report CMU/SEI-2003-TR-016, 2003. [Online].



REPORT DOCUMENTATION PAGE Form Approved

OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, search-ing existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regard-ing this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503.

1. AGENCY USE ONLY

(Leave Blank)

2. REPORT DATE

March 2010

3. REPORT TYPE AND DATES

COVERED

Final

4. TITLE AND SUBTITLE

Testing in Service-Oriented Environments

5. FUNDING NUMBERS

FA8721-05-C-0003

6. AUTHOR(S)

Ed Morris, William Anderson, Sriram Bala, David Carney, John Morley, Patrick Place, & Soumya Simanta

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

Software Engineering Institute

Carnegie Mellon University

Pittsburgh, PA 15213

8. PERFORMING ORGANIZATION REPORT NUMBER

CMU/SEI-2010-TR-011

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

HQ ESC/XPK

5 Eglin Street

Hanscom AFB, MA 01731-2116

10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

ESC-TR-2010-011

11. SUPPLEMENTARY NOTES

12A DISTRIBUTION/AVAILABILITY STATEMENT

Unclassified/Unlimited, DTIC, NTIS

12B DISTRIBUTION CODE

13. ABSTRACT (MAXIMUM 200 WORDS)

This report makes recommendations for testing service-oriented architecture (SOA) implementations consisting of infrastructure, servic-

es, and end-to-end processes. Testing implementations of SOA infrastructure, services, and end-to-end processing in support of busi-

ness processes is complex. SOA infrastructure is often composed of multiple, independently constructed commercial products―often

from different vendors―that must be carefully configured to interact in an appropriate manner. Services are loosely coupled components

which are intended to make minimal assumptions about where, why, and under what environmental conditions they are invoked. Busi-

ness processes link together multiple services and other systems in support of specific tasks. These services and systems may operate

on remote platforms controlled by different organizations and with different SOA infrastructures. Such complications make it difficult to

establish appropriate environments for tests, to ensure specific qualities of service, and to keep testing up-to-date with changing configu-

rations of platforms, infrastructure, services, and other components.

14. SUBJECT TERMS

SOA, service-oriented systems, service oriented architecture, web services, service testing

15. NUMBER OF PAGES

78

16. PRICE CODE

17. SECURITY CLASSIFICATION OF

REPORT

Unclassified

18. SECURITY CLASSIFICATION

OF THIS PAGE

Unclassified

19. SECURITY CLASSIFICATION

OF ABSTRACT

Unclassified

20. LIMITATION OF

ABSTRACT

UL

NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. Z39-18 298-102